U.S. patent application number 15/312290 was filed with the patent office on 2017-03-30 for support material for laminate shaping, product laminate-shaped by using the same, and laminate-shaped product production method.
This patent application is currently assigned to THE NIPPON SYNTHETIC CHEMICAL INDUSTRY CO., LTD.. The applicant listed for this patent is THE NIPPON SYNTHETIC CHEMICAL INDUSTRY CO., LTD.. Invention is credited to Shusaku MANDAI, Norihito SAKAI.
Application Number | 20170087775 15/312290 |
Document ID | / |
Family ID | 54699004 |
Filed Date | 2017-03-30 |
United States Patent
Application |
20170087775 |
Kind Code |
A1 |
SAKAI; Norihito ; et
al. |
March 30, 2017 |
SUPPORT MATERIAL FOR LAMINATE SHAPING, PRODUCT LAMINATE-SHAPED BY
USING THE SAME, AND LAMINATE-SHAPED PRODUCT PRODUCTION METHOD
Abstract
A laminate-shaping support material includes one of: a resin
composition containing a polyvinyl alcohol resin having a primary
hydroxyl group at its side chain, and having a heat of fusion of 10
to 30 J/g at its melting point (Embodiment (X)); and a resin
composition containing a polyvinyl alcohol resin, and a block
copolymer including a polymer block of an aromatic vinyl compound,
at least one of a polymer block of a conjugated diene compound and
a block of a hydrogenated conjugated diene compound, and a
functional group reactive with a hydroxyl group (Embodiment (Y)).
Therefore, the laminate shaping support material according to
Embodiment (X), for example, is excellent in shape stability and
adhesiveness to a model material. The laminate shaping support
material according to Embodiment (Y) is excellent in peelability
and forming stability.
Inventors: |
SAKAI; Norihito; (Osaka,
JP) ; MANDAI; Shusaku; (Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
THE NIPPON SYNTHETIC CHEMICAL INDUSTRY CO., LTD. |
Osaka |
|
JP |
|
|
Assignee: |
THE NIPPON SYNTHETIC CHEMICAL
INDUSTRY CO., LTD.
Osaka
JP
|
Family ID: |
54699004 |
Appl. No.: |
15/312290 |
Filed: |
May 28, 2015 |
PCT Filed: |
May 28, 2015 |
PCT NO: |
PCT/JP2015/065334 |
371 Date: |
November 18, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29K 2055/02 20130101;
B33Y 30/00 20141201; B29K 2829/04 20130101; B29C 67/00 20130101;
C08F 218/08 20130101; B29C 64/40 20170801; C08L 29/04 20130101;
C08L 53/02 20130101; B29C 64/106 20170801; B29K 2029/04 20130101;
B29K 2995/0039 20130101; B33Y 10/00 20141201; B29K 2995/0098
20130101; B29C 64/118 20170801; B29K 2995/0096 20130101; B33Y 70/00
20141201; C08F 218/08 20130101; C08F 218/14 20130101; C08L 29/04
20130101; C08L 53/02 20130101 |
International
Class: |
B29C 67/00 20060101
B29C067/00; C08L 29/04 20060101 C08L029/04; B33Y 70/00 20060101
B33Y070/00; B33Y 10/00 20060101 B33Y010/00; B33Y 30/00 20060101
B33Y030/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 29, 2014 |
JP |
2014-111373 |
Jul 2, 2014 |
JP |
2014-136886 |
Claims
1. A laminate shaping support material comprising a resin
composition comprising a polyvinyl alcohol resin including a
structural unit having a primary hydroxyl group at its side chain,
and having a heat of fusion of 10 to 30 J/g at its melting
point.
2. The laminate shaping support material according to claim 1,
wherein the structural unit is a structural unit having a 1,2-diol
structure at its side chain.
3. The laminate shaping support material according to claim 2,
wherein the structural unit having the 1,2-diol structure at its
side chain is a structural unit represented by the following
general formula (1): ##STR00005## wherein R.sup.1, R.sup.2 and
R.sup.3 are independently each a hydrogen atom or a C1 to C4 alkyl
group, X is a single bond or a bonding chain, R.sup.4, R.sup.5 and
R.sup.6 are independently each a hydrogen atom or a C1 to C4 alkyl
group.
4. The laminate shaping support material according to claim 7,
wherein the block copolymer has an acid value of 0.5 to 20 mg
CH.sub.3ONa/g.
5. A laminate comprising: the laminate-shaping support material
according to claim 1 and a model material, wherein a layer of the
laminate-shaping support material and a layer of the model material
are alternately laid one on another in a fluid state.
6. A laminate-shaped product production method comprising the steps
of: alternately laying a layer of the laminate-shaping support
material according to claim 1 and a layer of a model material one
on another in a fluid state; solidifying the support material and
the model material; and removing the support material.
7. A laminate shaping support material comprising a resin
composition comprising a polyvinyl alcohol resin, and a block
copolymer including a polymer block of an aromatic vinyl compound,
at least one of a polymer block of a conjugated diene compound and
a block of a hydrogenated conjugated diene compound, and a
functional group reactive with a hydroxyl group.
8. A laminate comprising: the laminate-shaping support material
according to claim 7 and a model material, wherein a layer of the
laminate-shaping support material and a layer of the model material
are alternately laid one on another in a fluid state.
9. A laminate-shaped product production method comprising the steps
of: alternately laying a layer of the laminate-shaping support
material according to claim 7 and a layer of a model material one
on another in a fluid state; solidifying the support material and
the model material; and removing the support material.
Description
TECHNICAL FIELD
[0001] The present invention relates to a laminate shaping support
material to be used for laminate shaping and thereafter removed
(hereinafter sometimes referred to simply as "support material")
and a product laminate-shaped by using the support material. The
invention further relates to a laminate-shaped product production
method. More specifically, the invention relates to a laminate
shaping support material which is excellent in shape stability,
adhesiveness to a model material, peelability and forming
stability.
[0002] The term "model material" means a material for the product
to be shaped, and the term "support material" means a
support-forming material which facilitates the shaping of the model
material and is removed after the shaping in most cases.
BACKGROUND ART
[0003] The term "laminate shaping" means a method of shaping a
three-dimensional product having a predetermined structure. A fluid
material is solidified immediately after being extruded, and
further laid over the solidified material, whereby the product is
shaped. A UV-curing method, a fusion laminate method and the like
are proposed for the laminate shaping method. The fusion laminate
method is widely employed because of the simplified structure of a
laminate shaping device.
[0004] The term "support material" means a material which is used
for the laminate shaping of the three-dimensional product to
complement the intended three-dimensional structure to fill an
absent portion of the structure. The three-dimensional product to
be laminate-shaped has a variety of structural portions and, in the
laminate shaping process, some of the structural portions cannot be
shaped without support with other material. The support material is
used for supporting the structural portions of the
three-dimensional product in the shaping process, and finally
removed.
[0005] Conventionally, a variety of support materials for the
laminate shaping are studied, which are classified into those that
are dissolved away in a liquid after the shaping, those that are
ground off after the shaping, and those that are blown off by a
liquid or a gas after the shaping.
[0006] Where the three-dimensional product has a complicated shape,
it is difficult to grind off the support material without any
damage to the product. The support material adapted to be blown off
problematically has an insufficient strength, failing to
sufficiently support the product. To cope with these problems, a
support material adapted to be dissolved away in a liquid is
proposed (PTL 1).
[0007] Exemplary water-soluble resins proposed for use as a support
material to be washed away with water include an amorphous
poly(2-ethyl-2-oxazoline) (PTL 2) and a polyvinyl alcohol
(hereinafter abbreviated as PVA) (PTL 3). Particularly, PTL 3
proposes that a styrene-ethylene-butylene-styrene block copolymer
(SEBS) is added to an amorphous PVA to impart the PVA with
flexibility. The amorphous water-soluble resin is less liable to
contract when being cooled to be solidified and, therefore, is
excellent in shape reproducibility.
[0008] Further, a variety of model materials for shaping the
three-dimensional product are studied, and an
acrylonitrile-butadiene-styrene (ABS) resin is mainly used in
consideration of melt formability, heat stability and mechanical
properties after solidification thereof.
RELATED ART DOCUMENT
Patent Document
[0009] PTL 1: JP-A-2014-24329
[0010] PTL 2: JP-A-2002-516346
[0011] PTL 3: US-A-2011-0060445
SUMMARY OF INVENTION
[0012] However, the support materials hitherto proposed are liable
to deform when a support material layer or a model material layer
is laid over a previously formed support material layer before the
previous layer is sufficiently cooled. Therefore, the support
materials suffer from unstable shape and insufficient adhesiveness
to the model material. This problematically reduces the shape
reproducibility due to an offset between the support material layer
and the model material layer. Therefore, the support materials are
unsatisfactory, and still require improvement.
[0013] Further, a method of entirely dissolving the support
material to actually remove the support material is time-consuming.
Therefore, a method to be generally employed is such that, after
the shaping, the support material is physically peeled off from the
model material to some extent and then a remaining portion of the
support material is dissolved away. The amorphous PVA proposed as
the support material in PTL 3 cannot be easily peeled off with
difficulty in deformation after the solidification, so that the
amount of the support material to be dissolved away is increased.
The support material prepared by adding the SEBS to the amorphous
PVA is soft and deformable, but is insufficient in toughness.
Therefore, the support material cannot be successfully peeled off,
but is torn. Further, the affinity between the PVA resin and the
SEBS is weak, so that the melt formability is unstable and the
shape reproducibility is reduced in the laminate shaping.
[0014] Thus, the conventional support materials are unsatisfactory
in the aforementioned aspects, still requiring improvement.
[0015] It is an object of the present invention to provide a
laminate shaping support material improved in shape stability,
adhesiveness to the model material, peelability and forming
stability without the aforementioned problems.
[0016] As a result of intensive studies in view of the foregoing,
the inventors of the present invention found that the
aforementioned problems are solved by using a resin composition
(Embodiment (X)) containing a PVA resin having a heat of fusion of
10 to 30 J/g at its melting point and including a structural unit
having a primary hydroxyl group at its side chain (preferably, a
PVA resin having a 1,2-diol structural unit at its side chain
wherein the structural unit having the primary hydroxyl group at
its side chain is a structural unit having a 1,2-diol structure at
its side chain (hereinafter sometimes referred to simply as
"1,2-diol-containing PVA resin")) or by using a resin composition
(Embodiment (Y)) containing a PVA resin and a block copolymer
including a polymer block of an aromatic vinyl compound, at least
one of a polymer block of a conjugated diene compound and a block
of a hydrogenated conjugated diene compound, and a functional group
reactive with a hydroxyl group (hereinafter sometimes referred to
simply as "block copolymer"), and attained the present
invention.
[0017] It is assumed that these effects are based on the following
mechanisms:
(1) Embodiment (X)
[0018] The heat of fusion of the PVA resin at the melting point is
an index indicating the crystallinity of the PVA resin. In order to
ensure the shape stability, it is conventionally considered
advantageous to use an amorphous water-soluble resin as the support
material. However, the studies conducted by the inventors reveal
that, where the amorphous support material is used, the shape
stability cannot be ensured. This is because, with a recent trend
toward increase in laminate-shaping speed, thermal deformation is
liable to occur when a support material layer or a model material
layer is laid over a support material layer previously formed by
melt-extruding the support material before the previous support
material layer is sufficiently cooled. To cope with this, a support
material excellent in shape stability and adhesiveness to the model
material is designed by employing the PVA resin having a specific
crystallinity (i.e., a heat of fusion of 10 to 30 J/g at its
melting point) and including the structural unit having the primary
hydroxyl group at its side chain (particularly, including the
1,2-diol structural unit at its side chain). Where the support
material has insufficient adhesiveness to the model material, an
offset occurs in an interface between the support material and the
model material, making it impossible to ensure the shape
reproducibility. Where the PVA resin having the primary hydroxyl
group at its side chain (particularly, the 1,2-diol-containing PVA
resin) is used for the support material, in contrast, the support
material has an improved affinity for the model material and hence
higher adhesiveness to the model material to be thereby improved in
shape reproducibility.
(2) Embodiment (Y)
[0019] The mechanism of the aforementioned effects is as follows.
With the PVA resin and the block copolymer forming a sea-island
structure, the support material per se is flexible and deformable.
Further, the block copolymer has the functional group reactive with
the hydroxyl group of the PVA resin. Therefore, when the support
material is peeled off, a sufficient adhesive force is provided in
an interface between the block copolymer serving as an island
component and the PVA resin serving as the sea component in the
support material. Thus, the support material is deformed without
cracking to be thereby removed from the model material without
fracture. Further, the block copolymer preferably has an affinity
for the PVA resin. Since the block copolymer has the functional
group reactive with the hydroxyl group of the PVA resin, the
support material melt-extruded for the laminate shaping has an
improved forming stability.
[0020] JP-A-2011-173998 proposes a latex which is prepared by
melt-kneading a PVA and a thermoplastic styrene elastomer having a
carboxylic acid group or a derivative of the carboxylic acid group
at its side chain and dispersing the thermoplastic styrene
elastomer in water with the PVA resin of the resulting mixture
dissolved in water. This literature neither states that the resin
composition (latex) containing the PVA resin and the thermoplastic
styrene elastomer having the carboxylic acid group is usable as a
support material for laminate shaping, nor discloses physical
properties of the resin composition required for the laminate
shaping and the formulation of the resin composition required for
the physical properties.
[0021] Further, JP-A-2011-74364 proposes a resin composition
containing a PVA polymer, a block copolymer including a polymer
block of an aromatic vinyl compound free from a carboxyl group and
at least one of a polymer block of a conjugated diene compound and
a block of a hydrogenated conjugated diene compound, and a block
copolymer having a carboxyl group. This literature mentions only
the flexural fatigue resistance and the gas barrier property of a
film formed from the resin composition, but neither states that the
resin composition is usable as a support material for laminate
shaping, nor discloses physical properties of the resin composition
required for the laminate shaping and the formulation of the resin
composition required for the physical properties.
[0022] According to a first aspect of the present invention, there
is provided a laminate shaping support material containing one
of:
(X) a resin composition containing a polyvinyl alcohol resin
including a structural unit having a primary hydroxyl group at its
side chain, and having a heat of fusion of 10 to 30 J/g at its
melting point (Embodiment (X)); and (Y) a resin composition
containing a polyvinyl alcohol resin, and a block copolymer
including a polymer block of an aromatic vinyl compound, at least
one of a polymer block of a conjugated diene compound and a block
of a hydrogenated conjugated diene compound, and a functional group
reactive with a hydroxyl group (Embodiment (Y)).
[0023] According to a second aspect of the present invention, there
is provided a product laminate-shaped by using the laminate-shaping
support material of the first aspect.
[0024] According to a third aspect of the present invention, there
is provided a laminate-shaped product production method including
the steps of: alternately laying a layer of the laminate-shaping
support material of the first aspect and a layer of a model
material one on another in a fluid state; solidifying the support
material and the model material; and removing the support
material.
[0025] The laminate shaping support material of Embodiment (X) of
the present invention is excellent in shape stability and
adhesiveness (adhesion) to the model material.
[0026] The laminate shaping support material of Embodiment (Y) of
the present invention is excellent in peelability and forming
stability.
DESCRIPTION OF EMBODIMENTS
[0027] The present invention provides laminate shaping support
materials, which respectively include resin compositions according
to two different embodiments. The laminate shaping support
materials according to the two embodiments of the present invention
will hereinafter be described.
Embodiment (X)
[0028] The laminate shaping support material according to
Embodiment (X) employs a resin composition (X) which contains a
specific PVA resin including a structural unit having a primary
hydroxyl group at its side chain, and having a heat of fusion of 10
to 30 J/g at its melting point.
[0029] The specific PVA resin will hereinafter be described in
detail.
[Specific PVA Resin]
[0030] The specific PVA resin to be used in Embodiment (X) includes
the structural unit having the primary hydroxyl group at its side
chain. The number of primary hydroxyl groups is typically 1 to 5,
preferably 1 to 2, particularly preferably 1. Further, the specific
PVA resin preferably has a secondary hydroxyl group in addition to
the primary hydroxyl group.
[0031] Examples of the specific PVA resin include a PVA resin
having a 1, 2-diol structural unit at its side chain, and a PVA
resin having a hydroxyalkyl group structural unit at its side
chain. Particularly, the PVA resin having the 1,2-diol structural
unit at its side chain preferred because the resulting support
material has an improved affinity for a model material and higher
adhesiveness to the model material.
[0032] In the specific PVA resin, the proportion (modification
ratio) of the structural unit having the primary hydroxyl group at
its side chain differs depending upon the type of the structural
unit, but typically 0.1 to 10 mol %. If the modification ratio is
excessively low, the support material tends to have a reduced
adhesiveness to the model material. If the modification ratio is
excessively high, the support material tends to have an excessively
low crystallization speed, resulting in deformation during laminate
shaping. Further, the support material tends have a lower adhesive
force with respect to the model material.
[0033] The specific PVA resin typically has an average
polymerization degree of 150 to 4000, preferably 200 to 2000 (as
measured in conformity with JIS K6726). If the average
polymerization degree is excessively low, stable shaping tends to
be difficult in the laminate shaping. If the average polymerization
degree is excessively high, the resin composition tends to have an
excessively high viscosity, making it difficult to perform a
melt-forming process.
[0034] The viscosity of an aqueous solution of the specific PVA
resin is sometimes employed as an index of the polymerization
degree of the PVA resin. The 1, 2-diol-containing PVA resin
typically has a viscosity of 1.5 to 20 mPas, preferably 2 to 12
mPas, particularly preferably 2.5 to 8 mPas. If the viscosity is
excessively low, stable shaping tends to be difficult in the
laminate shaping. If the viscosity is excessively high, the resin
composition tends to have an excessively high viscosity, making it
difficult to perform the melt-forming process.
[0035] The viscosity of the 1,2-diol-containing PVA resin herein
means a viscosity of a 4 wt. % aqueous solution of the
1,2-diol-containing PVA resin measured at 20.degree. C. in
conformity with JIS K6726.
[0036] The specific PVA resin typically has a saponification degree
of not less than 70 mol %, preferably not less than 80 mol %. If
the saponification degree is excessively low, the shape stability
tends to be reduced during the laminate shaping.
[0037] The saponification degree is measured in conformity with JIS
K6726.
[0038] Next, the PVA resin having the 1,2-diol structural unit at
its side chain will be described in detail.
[0039] A specific example of the PVA resin having the 1,2-diol
structural unit at its side chain is a PVA resin having a 1,2-diol
structural unit represented by the following general formula (1).
Since the PVA thus has the 1,2-diol structural unit at its side
chain, the support material is advantageously improved in affinity
for the model material. In the general formula (1), R.sup.1,
R.sup.2 and R.sup.3 are independently each a hydrogen atom or a C1
to C4 alkyl group, X is a single bond or a bonding chain, R.sup.4,
R.sup.5 and R.sup.6 are independently each a hydrogen atom or a C1
to C4 alkyl group.
##STR00001##
wherein R.sup.1, R.sup.2 and R.sup.3 are independently each a
hydrogen atom or a C1 to C4 alkyl group, X is a single bond or a
bonding chain, R.sup.4, R.sup.5 and R.sup.6 are independently each
a hydrogen atom or a C1 to C4 alkyl group.
[0040] The proportion (modification ratio) of the 1,2-diol
structural unit represented by the general formula (1) for the
1,2-diol-containing PVA resin is typically 0.1 to 10 mol %,
preferably 0.5 to 9 mol %, more preferably 2 to 8 mol %,
particularly preferably 3 to 8 mol %. If the modification ratio is
excessively low, the support material tends to have a reduced
adhesiveness to the model material. If the modification ratio is
excessively high, the support material tends to have an excessively
low crystallization speed, resulting in deformation during the
laminate shaping. Further, the support material tends to have a
lower adhesive force with respect to the model material. Like an
ordinary PVA resin, the 1,2-diol-containing PVA resin includes a
vinyl alcohol structural unit and an unsaponified vinyl ester
structural unit, in addition to the 1,2-diol structural unit.
[0041] In the 1,2-diol structural unit represented by the general
formula (1), R.sup.1 to R.sup.3 and R.sup.4 to R.sup.6 are
preferably all hydrogen atoms with the primary hydroxyl group being
present at a side chain terminal for improvement of the
adhesiveness to the model material. However, some of R.sup.1 to
R.sup.3 and R.sup.4 to R.sup.6 may be substituted with a C1 to C4
alkyl group, as long as the properties of the resin are not
significantly impaired. Examples of the C1 to C4 alkyl group
include a methyl group, an ethyl group, a n-propyl group, an
isopropyl group, a n-butyl group, an isobutyl group and a
tert-butyl group, which may have a substituent such as a halogen
atom, a hydroxyl group, an ester group, a carboxylic acid group or
a sulfonic acid group as required.
[0042] In the 1,2-diol structural unit represented by the general
formula (1), X is typically a single bond. For heat stability, X is
most preferably a single bond, but may be a bonding chain as long
as the effects of the present invention are not impaired. The
bonding chain is not particularly limited, but examples of the
bonding chain include hydrocarbons such as alkylenes, alkenylenes,
alkynylenes, phenylene and naphthylene (which may be substituted
with a halogen such as fluorine, chlorine or bromine), --O--,
--(CH.sub.2O).sub.m--, --(OCH.sub.2).sub.m--,
--(CH.sub.2O).sub.mCH.sub.2--, --CO--, --COCO--,
--CO(CH.sub.2).sub.mCO--, --CO(C.sub.6H.sub.4)CO--, --S--, --CS--,
--SO--, --SO.sub.2--, --NR--, --CONR--, --NRCO--, --CSNR--,
--NRCS--, --NRNR--, --HPO.sub.4--, --Si(OR).sub.2--,
--OSi(OR).sub.2--, --OSi(OR).sub.2O--, --Ti(OR).sub.2--,
--OTi(OR).sub.2--, --OTi(OR).sub.2O--, --Al(OR)--, --OAl(OR)-- and
--OAl(OR)O--, wherein Rs are independently each a given
substituent, preferably a hydrogen atom or an alkyl group, and m is
a natural number. Among these, the bonding chain is preferably an
alkylene group having a carbon number of not greater than 6 for
stability during production or during use, particularly preferably
a methylene group or --CH.sub.2OCH.sub.2--.
[0043] The 1,2-diol-containing PVA resin typically has an average
polymerization degree of 150 to 4000, preferably 200 to 2000,
particularly preferably 250 to 800 (as measured in conformity with
JIS K6726). If the average polymerization degree is excessively
low, stable shaping tends to be difficult in the laminate shaping.
If the average polymerization degree is excessively high, the melt
forming tends to be difficult.
[0044] The viscosity of an aqueous solution of the PVA resin is
sometimes employed as an index of the polymerization degree of the
PVA resin. The 1,2-diol-containing PVA resin typically has a
viscosity of 1.5 to 20 mPas, preferably 2 to 12 mPas, particularly
preferably 2.5 to 8 mPas. If the viscosity is excessively low,
stable shaping tends to be difficult in the laminate shaping. If
the viscosity is excessively high, the resin composition tends to
have an excessively high viscosity, making it difficult to perform
the melt-forming process.
[0045] The viscosity of the 1,2-diol-containing PVA resin herein
means a viscosity of a 4 wt. % aqueous solution of the
1,2-diol-containing PVA resin measured at 20.degree. C. in
conformity with JIS K6726.
[0046] The 1,2-diol-containing PVA resin typically has a
saponification degree of not less than 70 mol %, preferably 75 to
99.7 mol %, particularly preferably 87 to 99.5 mol %. If the
saponification degree is excessively low, the shape stability tends
to be reduced during the laminate shaping.
[0047] The saponification degree is measured in conformity with JIS
K6726.
[0048] The main chain of the PVA resin mainly has 1,3-diol bonds,
and the proportion of 1,2-diol bonds in the main chain is about 1.5
to about 1.7 mol %. The PVA resin to be used may contain the
1,2-diol bonds in a proportion increased to 2.0 to 3.5 mol % by
increasing the polymerization temperature in the polymerization of
the vinyl ester monomer.
[0049] In Embodiment (X), the PVA resin may be a copolymer obtained
by copolymerization with a small amount of other comonomer, as long
as the properties of the resin are not significantly influenced.
Examples of the comonomer include: olefins such as ethylene,
propylene, isobutylene, .alpha.-octene, .alpha.-dodecene and
.alpha.-octadecene; unsaturated acids such as acrylic acid,
methacrylic acid, crotonic acid, maleic acid, maleic anhydride and
itaconic acid, and salts, monoalkyl and dialkyl esters thereof;
nitriles such as acrylonitrile and methacrylonitrile; amides such
as acrylamide and methacrylamide; olefin sulfonic acids such as
ethylene sulfonic acid, allyl sulfonic acid and methallyl sulfonic
acid, and salts thereof; alkyl vinyl ethers, N-acrylamide methyl
trimethylammonium chloride, allyl trimethylammonium chloride,
dimethylallyl vinyl ketone, N-vinylpyrrolidone, vinyl chloride and
vinylidene chloride; polyoxyalkylene (meth)allyl ethers such as
polyoxyethylene (meth)allyl ethers and polyoxypropylene (meth)allyl
ethers; polyoxyalkylene (meth)acrylates such as polyoxyethylene
(meth)acrylates and polyoxypropylene (meth)acrylates;
polyoxyalkylene (meth)acrylamides such as polyoxyethylene
(meth)acrylamides and polyoxypropylene (meth)acrylamides; and
hydroxyl group-containing .alpha.-olefins such as polyoxyethylene
(1-(meth)acrylamide-1,1-dimethylpropyl) esters, polyoxyethylene
vinyl ethers, polyoxypropylene vinyl ethers, polyoxyethylene
allylamines, polyoxypropylene allylamines, polyoxyethylene
vinylamines, polyoxypropylene vinylamines, 3-buten-1-ol,
4-penten-1-ol and 5-hexen-1-ol, and acylation products and other
derivatives thereof.
[0050] The 1,2-diol-containing PVA resin typically has a melting
point of 120.degree. C. to 230.degree. C., preferably 150.degree.
C. to 220.degree. C., particularly preferably 160.degree. C. to
190.degree. C. If the melting point is excessively high, the resin
is liable to be deteriorated with the need for increasing the
process temperature in the laminate shaping. If the melting point
is excessively low, the shape stability tends to be reduced during
the laminate shaping.
[0051] In Embodiment (X), the PVA resin including the structural
unit having the primary hydroxyl group at its side chain,
preferably the 1, 2-diol-containing PVA resin, is required to have
a heat of fusion of 10 to 30 J/g, preferably 15 to 27 J/g,
particularly preferably 20 to 25 J/g, at its melting point. If the
heat of fusion is excessively high, the support material tends to
significantly shrink during solidification thereof and hence have
poorer shape stability. If the heat of fusion is excessively low, a
layer of the support material tends to deform when the next layer
is formed in the laminate shaping.
[0052] The method of measuring the heat of fusion at the melting
point will be described below in detail. A differential scanning
calorimeter of an input compensation type is used for the
measurement. The measurement is started at a measurement starting
temperature that is lower than the melting point by not less than
50.degree. C., typically about -30.degree. C. to about 30.degree.
C., and the measurement temperature is increased from the
measurement starting temperature at a temperature increase rate of
10.degree. C./min to a target temperature that is higher by about
30.degree. C. than the melting point so as prevent the thermal
decomposition of the resin. Thereafter, the measurement temperature
is reduced at a temperature decrease rate of 10.degree. C./min to
the measurement starting temperature, and then increased again at a
temperature increase rate of 10.degree. C./min to a target
temperature that is higher by about 30.degree. C. than the melting
point. The heat .DELTA.H (J/g) of fusion is calculated based on a
heat absorption peak area observed at the melting point in the
second temperature increase. The first target temperature and the
second target temperature are not necessarily required to be the
same. The amount of a sample to be used for the measurement differs
depending upon the measurement apparatus and the size of the
container (pan) to be used, but typically about 5 to about 10 mg.
If the amount of the sample is excessively great or excessively
small, the error of the measurement of the heat of fusion is
increased. What is important for the calculation of the heat
.DELTA.H of fusion is how to draw a base line. In an analysis
chart, an abscissa axis is defined as the axis of the temperature,
and the base line is defined as a straight line connecting a point
A at a temperature higher by 5.degree. C. than an end point of the
absorption peak of a DSC curve and a point B at a temperature lower
by 40.degree. C. than the apex of the heat absorption peak of the
DSC curve. The heat .DELTA.H of fusion is calculated based on an
area enclosed by the base line and the heat absorption peak.
[0053] The production method of the 1,2-diol-containing PVA resin
to be advantageously used in Embodiment (X) is not particularly
limited, but examples of the production method include: (i) a
method in which a copolymer of a vinyl ester monomer and a compound
represented by the following general formula (2) is saponified;
(ii) a method in which a copolymer of a vinyl ester monomer and a
compound represented by the following general formula (3) is
saponified and decarbonated; and (iii) a method in which a
copolymer of a vinyl ester monomer and a compound represented by
the following general formula (4) is saponified and deketalized.
The 1,2-diol-containing PVA resin may be produced, for example, by
a method described in paragraphs [0014] to [0037] in
JP-A-2008-163179.
##STR00002##
[0054] In the above general formulae (2), (3) and (4), R.sup.1,
R.sup.2, R.sup.3, X, R.sup.4, R.sup.5 and R.sup.6 are the same as
those for the general formula (1), and R.sup.7 and R.sup.8 are
independently each a hydrogen atom or R.sup.9--CO-- wherein R.sup.9
is a C1 to C4 alkyl group. R.sup.10 and R.sup.11 are independently
each a hydrogen atom or a C1 to C4 alkyl group.
[0055] [Laminate Shaping Support Material According to Embodiment
(X)]
[0056] The laminate shaping support material according to
Embodiment (X) is a resin composition which contains the PVA resin
including the structural unit having the primary hydroxyl group at
its side chain, preferably the 1,2-diol-containing PVA resin, as a
main component. The support material is generally formed into a
strand, which is wound around a reel and, in this state, set in a
laminate shaping apparatus. Therefore, the support material is
required to have flexibility and toughness that are sufficient to
prevent breakage when being wound around the reel. For practical
use, a flexible component is preferably added to the resin
composition. In the support material according to Embodiment (X),
the PVA resin including the structural unit having the primary
hydroxyl group at its side chain, preferably the
1,2-diol-containing PVA resin, is typically present in a proportion
of 50 to 100 wt. %, preferably 55 to 95 wt. %, particularly
preferably 60 to 90 wt. %, based on the overall weight of the
support material. If the proportion of the PVA resin is excessively
small, the support material tends to be poorer in dissolvability.
If the proportion of the PVA resin is excessively great, the
support material tends to be poorer in flexibility.
[0057] A thermoplastic resin is usable as the flexible component.
Examples of the thermoplastic resin include polyolefin resins,
polyester resins, polyamide resins, acryl resins, polyvinyl resins
(polyvinyl acetates, polyvinyl chlorides and the like) and
thermoplastic elastomers.
[0058] Examples of the thermoplastic elastomers include urethane
elastomers, ester elastomers and styrene elastomers. A block
copolymer including a polymer block of an aromatic vinyl compound,
and at least one of a polymer block of a conjugated diene compound
and a block of a hydrogenated conjugated diene compound is
preferably used as the thermoplastic elastomer. The block copolymer
preferably has a functional group reactive with a hydroxyl group to
impart the support material with toughness, and the functional
group is particularly preferably an acid. The block copolymer
preferably has an acid value of 1 to 10 mg CH.sub.3CONa/g,
particularly preferably 2 to 5 mg CH.sub.3CONa/g. The acid value is
measured by a neutralization titration method by which an alkali
consumption required for neutralization is determined.
[0059] The proportion of the flexible component is preferably 5 to
50 wt. %, more preferably 10 to 40 wt. %, particularly preferably
15 to 35 wt. %, based on the weight of the PVA resin including the
structural unit having the primary hydroxyl group at its side
chain.
[0060] A plasticizer may be added to the support material according
to Embodiment (X). In order to stabilize the shape of the support
material according to Embodiment (X), the proportion of the
plasticizer is preferably minimized, and preferably not greater
than 20 wt. %, more preferably not greater than 10 wt. %,
particularly preferably not greater than 1 wt. %, especially
preferably not greater than 0.1 wt. %.
[0061] In addition to the aforementioned component, known additives
such as a filler, an antioxidant, a colorant, an antistatic agent,
a UV absorber and a lubricant may be added to the resin composition
as required.
[0062] The support material according to Embodiment (X) has a melt
flow rate of 0.2 to 25 g/10 min, particularly preferably 1.0 to 15
g/min, more preferably 2.0 to 10 g/10 min, as measured at
210.degree. C. with a load of 2160 g in conformity with JIS K7210
as an index of the melt viscosity. If the melt viscosity is
excessively low, the support material is liable to drip from a
nozzle during the shaping, preventing proper shaping. If the melt
viscosity is excessively high, the nozzle is liable to be
clogged.
[0063] The production method of the support material of Embodiment
(X) for the laminate shaping includes the steps of: mixing the
aforementioned ingredients in predetermined proportions; kneading
the resulting mixture in a melted state with heating; extruding the
mixture into a strand; cooling the strand; and winding the strand
around a reel. More specifically, the aforementioned ingredients
are fed as a mixture or separately into a single-screw or
multi-screw extruder, heat-melted and kneaded, and extruded from a
single-hole or multi-hole strand die into a 1.5- to 3.0-mm diameter
strand, which is in turn cooled with air or with water to be
solidified and then wound around the reel. The strand is required
to have a stable diameter and have flexibility and toughness
sufficient to prevent breakage even if being wound around the reel.
Further, the strand is required to have rigidity sufficient to
ensure proper feed-out thereof to a head without delay in the
laminate shaping.
Embodiment (Y)
[0064] The laminate shaping support material according to
Embodiment (Y) employs a resin composition (Y) which contains a PVA
resin, and a block copolymer including a polymer block of an
aromatic vinyl compound, at least one of a polymer block of a
conjugated diene compound and a block of a hydrogenated conjugated
diene compound, and a functional group reactive with a hydroxyl
group.
[0065] [PVA Resin]
[0066] First, the PVA resin to be used in Embodiment (Y) will be
described.
[0067] The PVA resin is a resin mainly including a vinyl alcohol
structural unit and prepared by copolymerizing a vinyl ester
monomer and saponifying the resulting polyvinyl ester resin. The
PVA resin includes the vinyl alcohol structural unit in a
proportion corresponding to a saponification degree, and includes
an unsaponified vinyl ester structural unit.
[0068] Examples of the vinyl ester monomer include vinyl formate,
vinyl acetate, vinyl propionate, vinyl valerate, vinyl butyrate,
vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate,
vinyl stearate, vinyl benzoate and vinyl versatate, among which
vinyl acetate is preferably used for economy.
[0069] The PVA resin to be used in Embodiment (Y) typically has an
average polymerization degree of 150 to 4000, preferably 200 to
2000, particularly preferably 250 to 800, further preferably 300 to
600 (as measured in conformity with JIS K6726).
[0070] If the average polymerization degree is excessively low,
stable shaping tends to be difficult in the laminate shaping. If
the average polymerization degree is excessively high, the resin
composition tends to have an excessively high viscosity, making it
difficult to perform the melt-forming process.
[0071] The viscosity of an aqueous solution of the PVA resin is
sometimes employed as an index of the polymerization degree of the
PVA resin. The aqueous solution of the PVA resin to be used in
Embodiment (Y) typically has a viscosity of 1.5 to 20 mPas,
preferably 2 to 12 mPas, particularly preferably 2.5 to 8 mPas. If
the viscosity is excessively low, stable shaping tends to be
difficult in the laminate shaping. If the viscosity is excessively
high, the resin composition tends to have an excessively high
viscosity, making it difficult to perform the melt-forming
process.
[0072] As in Embodiment (X), the viscosity of the aqueous solution
of the PVA resin herein means a viscosity of a 4 wt. % aqueous
solution of the PVA resin measured at 20.degree. C. in conformity
with JIS K6726.
[0073] The PVA resin to be used in Embodiment (Y) typically has a
saponification degree of not less than 70 mol %, preferably 75 to
99.7 mol %, particularly preferably 85 to 99.5 mol %. If the
saponification degree is excessively low, the PVA resin tends to
have a reduced affinity for the block copolymer, thereby reducing
the shape stability in the laminate shaping.
[0074] The saponification degree is measured in conformity with JIS
K6726.
[0075] The PVA resin typically has a melting point of 120.degree.
C. to 230.degree. C., preferably 150.degree. C. to 220.degree. C.,
particularly preferably 190.degree. C. to 210.degree. C. If the
melting point is excessively high, the resin is liable to be
deteriorated with the need for increasing the process temperature
in the laminate shaping. If the melting point is excessively low,
the shape stability tends to be reduced during the laminate
shaping.
[0076] The main chain of the ordinary PVA resin mainly has 1,3-diol
bonds, and the proportion of 1,2-diol bonds in the main chain is
about 1.5 to about 1.7 mol %. The proportion of the 1,2-diol bonds,
which can be increased by increasing the polymerization temperature
for the polymerization of the vinyl ester monomer, is preferably
not less than 1.8 mol %, more preferably 2.0 to 3.5 mol % for
improvement of the affinity for the block copolymer.
[0077] In Embodiment (Y), a PVA resin prepared by copolymerizing a
comonomer in the preparation of the vinyl ester resin and
saponifying the resulting vinyl ester resin, and a modified PVA
resin prepared by introducing a functional group into an unmodified
PVA by a post modification reaction are usable as the PVA resin.
The modification degree of the PVA resin is generally not greater
than 20 mol % so that the PVA resin has sufficient water
solubility.
[0078] Examples of the comonomer to be used for the
copolymerization with the vinyl ester monomer include: olefins such
as ethylene, propylene, isobutylene, .alpha.-octene,
.alpha.-dodecene and .alpha.-octadecene; unsaturated acids such as
acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic
anhydride and itaconic acid, and salts, monoalkyl and dialkyl
esters thereof; nitriles such as acrylonitrile and
methacrylonitrile; amides such as acrylamide and methacrylamide;
olefin sulfonic acids such as ethylene sulfonic acid, allyl
sulfonic acid and methallyl sulfonic acid, and salts thereof; alkyl
vinyl ethers, N-acrylamide methyl trimethylammonium chloride, allyl
trimethylammonium chloride, dimethylallyl vinyl ketone,
N-vinylpyrrolidone, vinyl chloride, vinylidene chloride;
polyoxyalkylene (meth)allyl ethers such as polyoxyethylene
(meth)allyl ethers and polyoxypropylene (meth)allyl ethers;
polyoxyalkylene (meth)acrylates such as polyoxyethylene
(meth)acrylates and polyoxypropylene (meth)acrylates;
polyoxyalkylene (meth)acrylamides such as polyoxyethylene
(meth)acrylamides and polyoxypropylene (meth)acrylamides; and
hydroxyl group-containing .alpha.-olefins such as polyoxyethylene
(1-(meth)acrylamide-1,1-dimethylpropyl) esters, polyoxyethylene
vinyl ethers, polyoxypropylene vinyl ethers, polyoxyethylene
allylamines, polyoxypropylene allylamines, polyoxyethylene
vinylamines, polyoxypropylene vinylamines, 3-buten-1-ol,
4-penten-1-ol and 5-hexen-1-ol, and acylation products and other
derivatives thereof.
[0079] Examples of the PVA resin containing the functional group
introduced therein by the post reaction include a PVA resin having
an acetoacetyl group introduced therein by a reaction with a
diketene, a PVA resin having a polyalkylene oxide group introduced
therein by a reaction with ethylene oxide, a PVA resin having a
hydroxyalkyl group introduced therein by a reaction with an epoxy
compound or the like, and a PVA resin prepared by a reaction with
an aldehyde compound having a functional group.
[0080] The modification degree of the modified PVA resin, i.e., the
proportion of a structural unit derived from the comonomer in the
copolymer or the proportion of the functional group introduced in
the PVA resin by the post reaction, cannot be uniquely defined
because the physical properties of the modified PVA resin
significantly differ depending upon the type of the compound to be
used for the modification, but the modification degree is typically
0.1 to 20 mol %, particularly preferably 0.5 to 12 mol %.
[0081] Among these modified PVA resins, a PVA resin including a
structural unit having a primary hydroxyl group at its side chain
is preferably used in Embodiment (Y). The number of primary
hydroxyl groups is typically 1 to 5, preferably 1 to 2,
particularly preferably 1. The PVA resin preferably has a secondary
hydroxyl group in addition to the primary hydroxyl group.
[0082] Examples of the PVA resin including the structural unit
having the primary hydroxyl group at its side chain include a PVA
resin including a 1,2-diol structural unit at its side chain, and a
PVA resin including a hydroxyalkyl group structural unit at its
side chain, among which the PVA resin including the 1,2-diol
structural unit at its side chain (hereinafter sometimes referred
to simply as "1,2-diol-containing PVA resin" as in Embodiment (X))
is preferred because of its higher affinity for the block
copolymer. A PVA resin including a 1,2-diol structural unit
represented by the following general formula (1) at its side chain
is preferred as the 1,2-diol-containing PVA resin because of a
higher reactivity between the hydroxyl group of the block copolymer
and the functional group reactive with the hydroxyl group.
##STR00003##
wherein R.sup.1, R.sup.2 and R.sup.3 are independently each a
hydrogen atom or a C1 to C4 alkyl group, X is a single bond or a
bonding chain, and R.sup.4, R.sup.5 and R.sup.6 are independently
each a hydrogen atom or a C1 to C4 alkyl group.
[0083] The proportion (modification ratio) of the 1,2-diol
structural unit represented by the general formula (1) for the
1,2-diol-containing PVA resin is typically 0.5 to 12 mol %,
preferably 2 to 8 mol %, more preferably 3 to 8 mol %. If the
modification ratio is excessively low, the PVA resin tends to have
a lower reactivity with the functional group of the block
copolymer. If the modification ratio is excessively high, the
support material tends to have an excessively low crystallization
speed, resulting in deformation during the laminate shaping.
[0084] Like an ordinary PVA resin, the 1,2-diol-containing PVA
resin includes a vinyl alcohol structural unit and an unsaponified
vinyl ester structural unit, in addition to the 1,2-diol structural
unit.
[0085] In the 1,2-diol structural unit represented by the general
formula (1), R.sup.1 to R.sup.3 and R.sup.4 to R.sup.6 are
preferably all hydrogen atoms with the primary hydroxyl group being
present at a side chain terminal for further improvement of the
reactivity with the functional group of the block copolymer.
However, some of R.sup.1 to R.sup.3 and R.sup.4 to R.sup.6 may be
substituted with a C1 to C4 alkyl group, as long as the properties
of the resin are not significantly impaired. Examples of the C1 to
C4 alkyl group include a methyl group, an ethyl group, a n-propyl
group, an isopropyl group, a n-butyl group, an isobutyl group and a
tert-butyl group, which may have a substituent such as a halogen
atom, a hydroxyl group, an ester group, a carboxylic acid group or
a sulfonic acid group as required.
[0086] In the 1,2-diol structural unit represented by the general
formula (1), X is most preferably a single bond for heat stability
and stability under higher temperature conditions or acidic
conditions, but may be a bonding chain as long as the effects of
the present invention are not impaired. Examples of the bonding
chain include hydrocarbons such as alkylenes, alkenylenes,
alkynylenes, phenylene and naphthylene (which may be substituted
with a halogen such as fluorine, chlorine or bromine), --O--,
--(CH.sub.2O).sub.m--, --(OCH.sub.2).sub.m--,
--(CH.sub.2O).sub.mCH.sub.2--, --CO--, --COCO--,
--CO(CH.sub.2).sub.mCO--, --CO(C.sub.6H.sub.4)CO--, --S--, --CS--,
--SO--, --SO.sub.2--, --NR--, --CONR--, --NRCO--, --CSNR--,
--NRCS--, --NRNR--, --HPO.sub.4--, --Si(OR).sub.2--,
--OSi(OR).sub.2--, --OSi(OR).sub.2O--, --Ti(OR).sub.2--,
--OTi(OR).sub.2--, --OTi(OR).sub.2O--, --Al(OR)--, --OAl(OR)-- and
--OAl(OR)O--, wherein Rs are independently each a given
substituent, preferably a hydrogen atom or an alkyl group, and m is
an integer of 1 to 5. Among these, the bonding chain is preferably
an alkylene group having a carbon number of not greater than 6 for
stability during production or during use, particularly preferably
a methylene group or --CH.sub.2OCH.sub.2--.
[0087] The production method of the PVA resin having the 1,2-diol
structural unit at its side chain is not particularly limited, but
preferred examples of the production method include: (i) a method
in which a copolymer of a vinyl ester monomer and a compound
represented by the following general formula (2) is saponified;
(ii) a method in which a copolymer of a vinyl ester monomer and a
compound represented by the following general formula (3) is
saponified and decarbonated; and (iii) a method in which a
copolymer of a vinyl ester monomer and a compound represented by
the following general formula (4) is saponified and deketalized.
The PVA resin may be produced, for example, by a method described
in paragraphs [0014] to [0037] in JP-A-2008-163179.
##STR00004##
[0088] In the above general formulae (2), (3) and (4), R.sup.1,
R.sup.2, R.sup.3, X, R.sup.4, R.sup.5 and R.sup.6 are the same as
those for the general formula (1), and R.sup.7 and R.sup.8 are
independently each a hydrogen atom or R.sup.9--CO-- wherein R.sup.9
is a C1 to C4 alkyl group. R.sup.10 and R.sup.11 are independently
each a hydrogen atom or a C1 to C4 alkyl group.
[0089] The PVA resin to be used in Embodiment (Y) may be a single
type of PVA resin or a mixture of two or more types of PVA resins.
In the latter case, the aforementioned unmodified PVAs may be used
in combination, or any of the unmodified PVAs and the PVA resin
having the structural unit represented by the above general formula
(1) may be used in combination. Further, PVA resins each having the
structural unit represented by the above general formula (1) and
having different saponification degrees, different polymerization
degrees and different modification degrees may be used in
combination, or any of the unmodified PVAs or any of the PVA resins
having the structural unit represented by the above general formula
(1) and other modified PVA resin may be used in combination.
[0090] [Block Copolymer]
[0091] The support material according to Embodiment (Y) contains
the PVA resin and, in addition, the block copolymer including the
polymer block of the aromatic vinyl compound, at least one of the
polymer block of the conjugated diene compound and the block of the
hydrogenated conjugated diene compound, and the functional group
reactive with the hydroxyl group.
[0092] The block copolymer to be used in Embodiment (Y) will be
described.
[0093] The block copolymer to be used in Embodiment (Y) includes
the polymer block of the aromatic vinyl compound (typified by
styrene) as a hard segment, and the polymer block of the conjugated
diene compound, a hydrogenated block obtained by hydrogenating some
or all of remaining double bonds of the polymer block of the
conjugated diene compound or a polymer block of isobutylene as a
soft segment.
[0094] In Embodiment (Y), the block copolymer particularly
preferably has the functional group reactive with the hydroxyl
group at its side chain. More specifically, the block copolymer
preferably has a carboxylic acid group or a derivative of the
carboxylic acid group.
[0095] Where the hard segment is expressed by A and the soft
segment is expressed by B, the block copolymer may be a diblock
copolymer represented by A-B, a triblock copolymer represented by
A-B-A or B-A-B, or a polyblock copolymer including segments A and B
alternately arranged. The block copolymer may have a straight
structure, a branched structure or a star structure. The block
copolymer is preferably a straight triblock copolymer represented
by A-B-A from the viewpoint of kinetic properties.
[0096] Examples of a monomer to be used for formation of the
polymer block of the aromatic vinyl compound as the hard segment
include styrene; alkylstyrenes such as .alpha.-methylstyrene,
.beta.-methylstyrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, t-butylstyrene, 2,4-dimethylstyrene and
2,4,6-trimethylstyrene; halogenated styrenes such as
monofluorostyrene, difluorostyrene, monochlorostyrene,
dichlorostyrene and methoxystyrene; vinyl compounds such as
vinylnaphthalene, vinylanthracene, indene and acetonaphthylene
having an aromatic ring other than a benzene ring, and their
derivatives. The polymer block of the aromatic vinyl compound may
be a homopolymer block of a single monomer selected from the
aforementioned monomers or a copolymer block of plural monomers
selected from the aforementioned monomers. However, a styrene
homopolymer block is preferred.
[0097] The polymer block of the aromatic vinyl compound may be a
copolymer block formed by copolymerization with a small amount of a
monomer other than the aromatic vinyl compound, as long as the
effects of the present invention are not impaired. Examples of the
other monomer include olefins such as butene, pentene and hexene;
diene compounds such as butadiene and isoprene; vinyl ether
compounds such as methyl vinyl ether; and allyl ether compounds.
The copolymerization ratio is typically 10 mol % of the overall
polymer block.
[0098] The polymer block of the aromatic vinyl compound in the
block copolymer typically has a weight average molecular weight of
10,000 to 300,000, particularly preferably 20,000 to 200,000,
further preferably 50,000 to 100,000.
[0099] Examples of the monomer to be used for formation of the
polymer block as the soft segment include conjugated diene
compounds such as 1,3-butadiene, isoprene (2-methyl-1,3-butadiene),
2,3-dimethyl-1,3-butadiene and 1,3-pentadiene, and isobutylene,
which may be used alone or in combination. The polymer block is
preferably a homopolymer block or a copolymer block of isoprene,
butadiene and/or isobutylene. Particularly, the polymer block is
preferably a homopolymer of butadiene or isobutylene.
[0100] The polymer block of the conjugated diene compound has a
plurality of bonding arrangements depending upon the
polymerization. In the case of butadiene, for example, a butadiene
unit having 1,2-bonds (--CH.sub.2--CH(CH.dbd.CH.sub.2)--) and a
butadiene unit having 1,4-bonds (--CH.sub.2--CH.dbd.CH--CH.sub.2--)
are formed. The formation ratio of the diene units varies depending
upon the type of the conjugated diene compound, and cannot be
uniquely defined. In the case of butadiene, the 1,2-bond formation
ratio is typically 20 to 80 mol %.
[0101] By hydrogenating some or all of the remaining double bonds
of the polymer block of the conjugated diene compound, the heat
resistance and the weather resistance of the thermoplastic styrene
elastomer can be improved. At this time, the hydrogenation ratio is
preferably not less than 50 mol %, particularly preferably not less
than 70 mol %.
[0102] For example, the hydrogenation converts the butadiene unit
having the 1,2-bonds into a butylene unit
(--CH.sub.2--CH(CH.sub.2--CH.sub.3)--), and converts the butadiene
unit having the 1, 4-bonds into two continuous ethylene units
(--CH.sub.2--CH.sub.2--CH.sub.2--CH.sub.2--). Generally, the former
unit is preferentially formed.
[0103] The polymer block serving as the soft segment may be a
copolymer block formed by copolymerization with a small amount of a
monomer other than the aforementioned monomers. Examples of the
other monomer include aromatic vinyl compounds such as styrene,
olefins such as butene, pentene and hexene, vinyl ether compounds
such as methyl vinyl ether, and allyl ether compounds. The
copolymerization ratio of the other monomer is generally not
greater than 10 mol % of the overall polymer block.
[0104] The polymer block of the conjugated diene compound or
isobutylene in the block copolymer typically has a weight average
molecular weight of 10,000 to 300,000, particularly preferably
20,000 to 200,000, further preferably 50,000 to 100,000.
[0105] As described above, the block copolymer to be used in
Embodiment (Y) of the present invention includes the polymer block
of the aromatic vinyl compound as the hard segment, and the polymer
block of the conjugated diene compound or the polymer block
obtained by hydrogenating some or all of the remaining double bonds
of the conjugated diene compound and the polymer block of
isobutylene as the soft segment. Typical examples of the block
copolymer include a styrene/butadiene block copolymer (SBS)
prepared by using styrene and butadiene as ingredients, a
styrene/butadiene/butylene block copolymer (SBBS) obtained by
hydrogenating side chain double bonds of the butadiene structural
unit of the SBS, a styrene/ethylene/butylene block copolymer (SEBS)
obtained by hydrogenating main chain double bonds, a
styrene/isoprene block copolymer (SIPS) prepared by using styrene
and isoprene as ingredients, and a styrene/isobutylene block
copolymer (SIBS) prepared by using styrene and isobutylene as
ingredients. Particularly, the SEBS and the SIBS are preferably
used, which are excellent in heat stability and weather
resistance.
[0106] The weight ratio between the polymer block of the aromatic
vinyl compound serving as the hard segment and the polymer blocks
serving as the soft segment in the block copolymer is typically
10/90 to 70/30, particularly preferably 20/80 to 50/50. If the
proportion of the polymer block of the aromatic vinyl compound is
excessively great or excessively small, the balance between the
flexibility and the elasticity of the block copolymer is
deteriorated. As a result, the support material is insufficient in
peelability and other properties.
[0107] The block copolymer can be produced by preparing the block
copolymer including the polymer block of the aromatic vinyl
compound and the polymer block of the conjugated diene compound or
isobutylene and, as required, hydrogenating double bonds of the
polymer block of the conjugated diene compound.
[0108] A known method may be used for the production of the block
copolymer including the polymer block of the aromatic vinyl
compound and the polymer block of the conjugated diene compound or
isobutylene. For example, the production of the block copolymer may
be achieved by sequentially polymerizing the aromatic vinyl
compound and the conjugated diene compound or isobutylene in an
inactive organic solvent with the use of an alkyllithium compound
or the like as an initiator.
[0109] A known method may be used for the hydrogenation of the
block copolymer including the polymer block of the aromatic vinyl
compound and the polymer block of the conjugated diene compound.
For example, the hydrogenation may be achieved by using a reducing
agent such as a hydrogenated boron compound, or by using a metal
catalyst such as platinum, palladium or Raney nickel for hydrogen
reduction.
[0110] A characteristic feature of the present invention is that
the block copolymer to be used in Embodiment (Y) has the functional
group reactive with the hydroxyl group at its side chain. The
functional group is preferably a carboxylic acid. The support
material produced by using the block copolymer having the
functional group reactive with the hydroxyl group at its side chain
is excellent particularly in peelability and forming stability.
[0111] The amount of the carboxylic acid to be contained in the
block copolymer is typically 0.5 to 20 mg CH.sub.3ONa/g,
particularly preferably 1 to 10 mg CH.sub.3ONa/g, further
preferably 1.5 to 3 mg CH.sub.3ONa/g, which is measured as acid
value by a titration method.
[0112] If the acid value is excessively low, it will be impossible
to sufficiently provide the effect of introducing the functional
group into the block copolymer. If the acid value is excessively
high, the support material tends to have an excessively high melt
viscosity due to a crosslinking reaction.
[0113] A known method may be used for the introduction of the
carboxylic acid-containing functional group into the block
copolymer. Preferred examples of the method include a method in
which an .alpha.,.beta.-unsaturated carboxylic acid or its
derivative is copolymerized in the production of the block
copolymer (i.e., during the copolymerization), and a method in
which an .alpha.,.beta.-unsaturated carboxylic acid or its
derivative is added to the block copolymer after the production of
the block copolymer. Specific examples of the addition method
include a method in which the addition is achieved by a radical
reaction in a solution in the presence or absence of a radical
initiator, and a method in which the block copolymer and the
.alpha.,.beta.-unsaturated carboxylic acid or its derivative are
melt-kneaded in an extruder.
[0114] Examples of the .alpha.,.beta.-unsaturated carboxylic acid
or its derivative to be used for the introduction of the carboxylic
acid group include .beta.-unsaturated monocarboxylic acids such as
acrylic acid and methacrylic acid; .alpha.,.beta.-unsaturated
dicarboxylic acids such as maleic acid, succinic acid, itaconic
acid and phthalic acid; and .alpha.,.beta.-unsaturated
monocarboxylic acid esters such as glycidyl acrylate, glycidyl
methacrylate, hydroxyethyl acrylate and hydroxymethyl methacrylate.
In Embodiment (Y) of the present invention, adjacent carboxylic
acid groups introduced into the block copolymer may form an acid
anhydride structure. Examples of the acid anhydride structure
include .alpha.,.beta.-unsaturated dicarboxylic acid anhydrides
such as maleic anhydride, succinic anhydride, itaconic anhydride
and phthalic anhydride.
[0115] The block copolymer to be used in Embodiment (Y) typically
has a weight average molecular weight of 50,000 to 500,000,
particularly preferably 120,000 to 450,000, further preferably
150,000 to 400,000.
[0116] If the weight average molecular weight is excessively great
or excessively small, or if the melt viscosity to be described
below is excessively high or excessively low, the resin composition
fails to have homogenous morphology with the block copolymer
homogeneously dispersed in the PVA resin and, therefore, tends to
have poorer mechanical properties.
[0117] The weight average molecular weight of the block copolymer
is measured by a gel permeation chromatography (GPC) based on a
polystyrene calibration standard.
[0118] The block copolymer typically has a melt viscosity of 100 to
3000 mPas, particularly preferably 300 to 2000 mPas, further
preferably 800 to 1500 mPas, as measured at 220.degree. C. with a
shearing speed of 122 sec.sup.-1.
[0119] In Embodiment (Y), the block copolymer may include a single
type of block copolymer, or may include plural types of block
copolymers in order to impart the resin composition with desired
properties.
[0120] Commercially available examples of the block copolymer
having the reactive functional group include TOUGHTECH M series
(carboxyl group-modified SEBS) available from Asahi Kasei
Corporation, f-DYNARON available from JSR Corporation, and KRATON
FG available from Shell Japan Co.
[0121] [Laminate Shaping Support Material According to Embodiment
(Y)]
[0122] The laminate shaping support material according to
Embodiment (Y) contains the PVA resin and the block copolymer. The
proportion of the PVA resin is preferably 50 to 95 wt. %, more
preferably 60 to 90 wt. %, particularly preferably 65 to 75 wt. %,
based on the total weight of the PVA resin and the block copolymer
in the support material. If the proportion is less than 50 wt. %,
the support material tends to have a reduced water solubility. If
the proportion is greater than 95 wt. %, the support material tends
to have a reduced flexibility.
[0123] The proportion of the PVA resin is 50 to 95 wt. %,
preferably 60 to 90 wt. %, particularly preferably 70 to 80 wt. %,
based on the overall weight of the support material. If the
proportion is excessively small, the support material tends to have
a significantly reduced water solubility. If the proportion is
excessively great, the support material tends to have an
insufficient flexibility.
[0124] The proportion of the block copolymer is preferably 5 to 50
wt. %, more preferably 10 to 40 wt. %, particularly preferably 25
to 35 wt. %, based on the total weight of the PVA resin and the
block copolymer. If the proportion is less than 5 wt. %, the
support material tends to have an insufficient flexibility. If the
proportion is greater than 50 wt. %, the support material tends to
have poorer forming stability with an excessively high melt
viscosity.
[0125] The proportion of the block copolymer is 5 to 50 wt. %,
preferably 10 to 40 wt. %, particularly preferably 20 to 30 wt. %,
based on the overall weight of the support material. If the
proportion is excessively small, the support material tends to have
an insufficient flexibility. If the proportion is excessively
great, the support material tends to have poorer forming
stability.
[0126] Since the support material is fed in the form of a strand to
a head of the laminate shaping apparatus, the support material
preferably has a proper rigidity for smooth feeding thereof.
Further, the strand of the support material is often fed through a
tube to the head of the laminate shaping apparatus. Therefore, the
support material preferably has a surface highly slidable with
respect to an interior surface of the tube. Accordingly, the
surface of the support material is preferably smooth and free from
tackiness for the smooth feeding of the strand of the support
material to the head of the laminate shaping apparatus. In general,
a strand surface of the PVA resin is highly hygroscopic and hence
liable to be tacky. Therefore, a filler is preferably added to the
support material in order to impart the strand of the support
material with proper rigidity and to suppress the tackiness of the
strand.
[0127] The filler may be an organic filler or an inorganic filler.
For excellent heat stability, the inorganic filler is preferred.
Examples of the inorganic filler include oxides, hydroxides,
carbonates, sulfates, silicates, nitrides, carbon compounds and
metals, among which the silicates are preferred because they have
no adverse influence on the heat stability of the support material.
Examples of the silicates include calcium silicate, talc, clay,
mica, montmorillonite, bentonite, activated clay, sepiolite,
imogolite, sericite, glass fibers, glass beads and silica balloons,
among which the talc is preferred because it improves the surface
smoothness of the support material and alleviates the tackiness of
the support material. The filler preferably has a particle size of
0.5 to 500 .mu.m, more preferably 50 to 400 .mu.m, particularly
preferably 100 to 300 .mu.m. The talc preferably has a particle
size of 0.5 to 10 .mu.m, more preferably 1 to 5 .mu.m, particularly
preferably 2 to 3 .mu.m. If the particle size is excessively small,
it will be difficult to knead the filler in the resin. If the
particle size is excessively great, the support material tends to
have a rough surface and a lower strength. Industrially preferred
examples of the filler include SG-95 and SG-200 available from
Nippon Talc Co., Ltd., and LSM-400 available from Fuji Talc
Industrial Co., Ltd. The particle size herein means a particle
diameter D50 measured by a laser diffraction method. The proportion
of the filler is preferably 1 to 40 wt. %, more preferably 2 to 30
wt. %, particularly preferably 3 to 10 wt. %, based on the weight
of the support material. If the proportion of the filler is
excessively small, the effect of the addition of the filler cannot
be provided. If the proportion of the filler is excessively great,
the strand of the support material tends to have a reduced surface
smoothness and a reduced flexibility.
[0128] The support material may contain a plasticizer. In
Embodiment (Y), however, the proportion of the plasticizer is
preferably minimized in order to improve the forming stability of
the support material, and is preferably not greater than 20 wt. %,
more preferably not greater than 10 wt. %, further preferably not
greater than 1 wt. %, particularly preferably not greater than 0.1
wt. %.
[0129] In addition to the aforementioned ingredients, as required,
known additives such as an antioxidant, a colorant, an antistatic
agent, a UV absorber and a lubricant, and other thermoplastic resin
may be added to the resin composition. Specific examples of the
other thermoplastic resin include olefin homopolymers and
copolymers such as linear low-density polyethylenes, low-density
polyethylenes, medium-density polyethylenes, high-density
polyethylenes, ethylene-vinyl acetate copolymers, ionomers,
ethylene-propylene copolymers, ethylene-.alpha.-olefin (C4 to C20
.alpha.-olefin) copolymers, ethylene-acrylate copolymers,
polypropylenes, propylene-.alpha.-olefin (C4 to C20 .alpha.-olefin)
copolymers, polybutenes and polypentenes, polycycloolefins,
polyolefin resins in a broader sense such as obtained by
graft-modifying any of these olefin homopolymers and copolymers
with an unsaturated carboxylic acid or an unsaturated carboxylate,
polystyrene resins, polyesters, polyamides, copolymerized
polyamides, polyvinyl chlorides, polyvinylidene chlorides, acrylic
resins, vinyl ester resins, polyurethane elastomers, chlorinated
polyethylenes and chlorinated polypropylenes.
[0130] As in Embodiment (X), the production method of the support
material to be used for the laminate shaping includes the steps of
mixing the aforementioned ingredients in predetermined proportions,
kneading the resulting mixture in a melted state with heating,
extruding the mixture into a strand, cooling the strand and winding
the strand around a reel. More specifically, the ingredients are
fed as a mixture or separately into a single screw or multi-screw
extruder, heat-melted and kneaded, and extruded from a single-hole
or multi-hole strand die into a 1.5- to 3.0-mm diameter strand,
which is in turn cooled with air or with water to be solidified and
then wound around the reel. The strand is required to have a stable
diameter and have flexibility and toughness sufficient to prevent
breakage even if being wound around the reel. Further, the strand
is required to have rigidity sufficient to ensure proper feed-out
thereof to the head without delay in the laminate shaping.
[0131] [Laminate-Shaped Product Production Method and
Laminate-Shaped Product]
[0132] A laminate-shaped product production method employing the
inventive support material will be described.
[0133] A known laminate shaping apparatus may be used as the
laminate shaping apparatus for the laminate shaping, as long as the
apparatus includes a plurality of heads respectively adapted to
extrude the model material and the support material and is capable
of performing a fusion laminate shaping process. Examples of the
laminate shaping apparatus include dual head type laminate shaping
apparatuses such as CREATOR available from Flashforge Co., Ltd.,
EAGLEED available from Reis Enterprise Co., Ltd., MBOT Grid II
available from 3D Systems Corporation and UPRINT SE available from
Stratasys Ltd. Exemplary materials to be used as the model material
for forming a three-dimensional product include various resins such
as acrylonitrile butadiene styrene (ABS) resins, polylactic acids,
polystyrenes, polyamides and polyethylenes, among which the ABS
resins are mainly used from the viewpoint of melt-formability, heat
stability and mechanical properties after solidification. The
support material is required to have excellent adhesiveness to the
ABS resins.
[0134] Like the support material, the model material is formed into
a strand, which is in turn wound around a reel. The strands of the
model material and the support material are respectively fed to
separate heads of the laminate shaping apparatus, melted in the
heads with heating, and applied in a fluid state onto a stage from
separate nozzles to be pressed against the stage and laid one over
another. The melting temperatures in the heads are typically
150.degree. C. to 220.degree. C., and the extruding pressures are
typically 200 to 1000 psi. The laminating pitch is typically 200 to
350 .mu.m.
[0135] A laminate thus formed from the support material and the
model material is cooled to be solidified, and then the support
material is removed from the laminate, whereby the intended
laminate-shaped product is produced. For example, the inventive
support material is dissolved away in water. To dissolve away the
support material, the laminate may be immersed in water or hot
water contained in a container, or the support material may be
washed away from the laminate with running water. Where the
dissolution of the support material is achieved by immersing the
laminate in water, it is preferred to stir the water or apply
ultrasonic waves to the water in order to reduce the dissolution
process time. The temperature of the water is preferably about
25.degree. C. to about 80.degree. C. The weight of the water or the
hot water to be used for the dissolution of the support material is
about 10 to about 10000 times the weight of the support material. A
characteristic feature of the inventive support material is that
the support material can be easily dissolved away in water at a
relatively low temperature.
EXAMPLES
[0136] The present invention will hereinafter be described more
specifically by way of examples thereof. It should be understood
that the present invention be not limited to these examples within
the scope of the invention. In the examples, the term "part(s)"
means part(s) by weight.
Examples of Embodiment (X)
Example 1
(i) Preparation of 1,2-Diol-Containing PVA Resin (1)
[0137] In a reaction vessel provided with a reflux condenser, a
dropping funnel and a stirrer, 10% of 68.5 parts of vinyl acetate
and 20.5 parts of methanol were first fed, and the rest of the
vinyl acetate and 11.0 parts (7.2 mol % with respect to the amount
of vinyl acetate to be fed) of 3,4-diacetoxy-1-butene were fed
dropwise at constant rates in 9 hours. Then, 0.3 mol % (with
respect to the amount of the fed vinyl acetate) of
azobisisobutyronitrile was fed into the reaction vessel. In turn,
the temperature was raised while the resulting mixture was stirred
in a nitrogen stream, thereby initiating polymerization. When the
polymerization degree of vinyl acetate reached 90%, a predetermined
amount of m-dinitrobenzene was added to the reaction vessel to
terminate the polymerization. Subsequently, methanol vapor was
blown into the reaction vessel, whereby unreacted vinyl acetate
monomer was removed out of the reaction vessel. Thus, a copolymer
was prepared in the form of a methanol solution.
[0138] The methanol solution was further diluted with methanol to a
concentration of 45 wt. %, and fed into a kneader. Then, a methanol
solution of sodium hydroxide having a sodium concentration of 2 wt.
% was added in a proportion of 10.5 mmol based on a total amount of
1 mol of a vinyl acetate structural unit and a
3,4-diacetoxy-1-butene structural unit of the copolymer with the
solution temperature kept at 35.degree. C., and the copolymer was
saponified for 4 hours. As the saponification proceeded, a
saponification product was precipitated. When the saponification
product was obtained in a particulate form, the saponification
product was separated by a solid/liquid separation process. The
resulting saponification product was thoroughly rinsed with
methanol, and dried at 70.degree. C. for 12 hours in a hot air
dryer. Thus, an intended 1,2-diol-containing PVA resin (1) was
prepared.
[0139] The 1,2-diol-containing PVA resin (1) thus prepared had a
saponification degree of 99.0 mol % as determined by measuring an
alkali consumption required for hydrolysis of vinyl acetate
remaining in the resin and the structural unit of
3,4-diacetoxy-1-butene. The PVA resin (1) had an average
polymerization degree of 360 as determined by analysis in
conformity with JIS K6726, and a melting point of 175.degree. C. as
measured by a differential thermal analyzer DSC. The content of the
1,2-diol structural unit represented by the formula (1) was 7.2 mol
% as calculated from an integration value measured by .sup.1H-NMR
(300 MHz proton NMR using a d6-DMSO solution and an internal
standard of tetramethylsilane at 50.degree. C.).
[0140] The PVA resin (1) had a heat (.DELTA.H) of fusion of 21.5
J/g at its melting point as measured by means of a Perkin-Elmer's
input compensation type differential scanning calorimeter "Diamond
DSC" by sealing 5 mg of a sample in a measurement pan, increasing
the temperature at a temperature increase rate of 10.degree. C./min
from -30.degree. C. to 215.degree. C., immediately thereafter
reducing the temperature at a temperature decrease rate of
10.degree. C./min to -30.degree. C. and increasing the temperature
again at a temperature increase rate of 10.degree. C./min to
230.degree. C.
(ii) Production of Support Material
[0141] The 1,2-diol-containing PVA resin (1) was fed into a twin
screw extruder, melted and kneaded under the following conditions
and extruded into a strand having a diameter of 1.75 mm, and the
strand was cooled on a belt and wound around a reel. Thus, a
support material was produced. The support material was evaluated
in the following manner. The results of the evaluation are shown in
Table 1.
Extruder: Available from Technovel Corporation, and having a
diameter of 15 mm and an L/D ratio of L/D=60 Extruding temperature:
C1/C2/C3/C4/C5/C6/C7/C8/D=150.degree. C./170.degree. C./180.degree.
C./190.degree. C./200.degree. C./210.degree. C./230.degree.
C./230.degree. C./230.degree. C. Rotation speed: 200 rpm Discharge
amount: 1.5 kg/hour
(iii) Evaluation of Support Material
[Shape Stability]
[0142] A plate of the support material was prepared by means of an
injection molding machine PS60E12ASE available from Nissei Ltd. by
using a plate mold having a size of 5.0.times.2.5 cm and a
thickness of 2 mm and employing an injection temperature of
210.degree. C., an injection speed of 50%, an injection pressure of
60%, a mold temperature of 70.degree. C. and a cooling period of 30
seconds. The plate was placed on a hot plate at 80.degree. C. to be
heated. After 3.0 g of an ABS resin TOYORAC Grade 600-309 available
from Toray Corporation was extruded in a melted state onto the
support material plate at 230.degree. C. at a discharge rate of 0.5
kg/hour by means of a 15 mm.phi. single screw extruder, the support
material plate was removed from the hot plate and sufficiently
cooled in a 25.degree. C. atmosphere. When the ABS resin was
thereafter peeled off from the support material plate, the state of
the surface of the plate was visually checked, and rated based on
the following criteria:
Excellent (oo): The plate was not deformed at all. Acceptable (o):
The plate was slightly deformed. Unacceptable (x): The plate was
apparently deformed.
[0143] [Adhesiveness to Model Material]
[0144] An ABS resin TOYORAC Grade 600-309 available from Toray
Corporation was extruded to be formed into a single layer film
having a thickness of 30 .mu.m, and the support material was laid
over the single layer film to a thickness of 5 .mu.m under the
following conditions by an extrusion coating method. The resulting
double layer film was cut to a width of 15 mm, and a T-peeling test
was performed on the resulting strip at a peeling rate of 100
mm/min in conformity with JIS K6854-3 for evaluation of the support
material for adhesiveness.
Extruder: Available from Technovel Corporation, and having a
diameter of 15 mm and an L/D ratio of L/D=60 Die: A 30-cm width
coat hanger die having a lip opening size of 0.35 mm Extruding
temperature: C1/C2/C3/C4/C5/C6/C7/C8/D=150.degree. C./170.degree.
C./180.degree. C./190.degree. C./200.degree. C./210.degree.
C./230.degree. C./230.degree. C./230.degree. C. Discharge amount:
0.5 kg/hour
Example 2
(i) Preparation of 1,2-Diol-Containing PVA Resin (2)
[0145] In substantially the same manner as in Example 1, 40% of
72.1 parts of vinyl acetate and 21.6 parts of methanol were first
fed in a reaction vessel, and the rest of the vinyl acetate and 6.3
parts of 3,4-diacetoxy-1-butene were fed dropwise at constant rates
in 8 hours. Then, 0.16 mol % (with respect to the amount of the fed
vinyl acetate) of azobisisobutyronitrile was fed in the reaction
vessel. In turn, the temperature was raised while the resulting
mixture was stirred in a nitrogen stream, thereby initiating
polymerization. When the polymerization degree of vinyl acetate
reached 90%, a predetermined amount of m-dinitrobenzene was added
to the reaction vessel to terminate the polymerization.
Subsequently, methanol vapor was blown into the reaction vessel,
whereby unreacted vinyl acetate monomer was removed out of the
reaction vessel. Thus, a copolymer was prepared in the form of a
methanol solution.
[0146] The methanol solution was further diluted with methanol to a
concentration of 55 wt. %, and fed into a kneader. Then, a methanol
solution of sodium hydroxide having a sodium concentration of 2 wt.
% was added in a proportion of 3.0 mmol based on a total amount of
1 mol of a vinyl acetate structural unit and a
3,4-diacetoxy-1-butene structural unit of the copolymer with the
solution temperature kept at 35.degree. C., whereby the copolymer
was saponified. As the saponification proceeded, a saponification
product was precipitated. When the saponification product was
obtained in a particulate form, the saponification product was
separated by a solid/liquid separation process. The resulting
saponification product was thoroughly rinsed with methanol, and
dried in a hot air dryer. Thus, an intended 1,2-diol-containing PVA
resin (2) was prepared.
[0147] The 1,2-diol-containing PVA resin (2) thus prepared had a
saponification degree of 78.0 mol %, an average polymerization
degree of 450, a 1,2-diol structural unit content of 4.5 mol %, a
melting point of 143.degree. C., and a heat (.DELTA.H) of fusion of
14.3 J/g.
[0148] In the same manner as in Example 1, the 1,2-diol-containing
PVA resin (2) thus prepared was kneaded by means of a twin screw
extruder, and formed into a strand-shaped support material, which
was in turn evaluated.
Comparative Example 1
(i) Preparation of 1,2-Diol-Containing PVA Resin (3)
[0149] In a reaction vessel provided with a reflux condenser, a
dropping funnel and a stirrer, 27.1 parts (40 wt. % of the total
feed amount) of vinyl acetate, 14.2 parts of methanol and 7.2 parts
(40 wt. % of the total feed amount) of 3,4-diacetoxy-1-butene were
first fed, and then 0.06 mol % (with respect to the amount of the
fed vinyl acetate) of azobisisobutyronitrile was fed. In turn, the
temperature was raised while the resulting mixture was stirred in a
nitrogen stream, thereby initiating polymerization.
[0150] Further, 40.7 parts (60 wt. % of the total feed amount) of
vinyl acetate and 10.8 parts (60 wt. % of the total feed amount) of
3,4-diacetoxy-1-butene were fed dropwise at constant rates in the
reaction vessel in 15 hours, during which 0.04 mol % (with respect
to the amount of the fed vinyl acetate) of azobisisobutyronitrile
was additionally fed dividedly in two parts into the reaction
vessel and the polymerization was continued. When the
polymerization degree of vinyl acetate reached 90%, a predetermined
amount of m-dinitrobenzene was added to the reaction vessel to
terminate the polymerization. Subsequently, methanol vapor was
blown into the reaction vessel, whereby unreacted vinyl acetate was
removed out of the reaction vessel. Thus, a copolymer was prepared
in the form of a methanol solution.
[0151] Then, the methanol solution was further diluted with
methanol to a concentration of 55 wt. %, and fed into a kneader.
Then, a methanol solution of sodium hydroxide having a sodium
concentration of 2 wt. % was added in a proportion of 3.5 mmol
based on a total amount of 1 mol of a vinyl acetate structural unit
and a 3,4-diacetoxy-1-butene structural unit of the copolymer with
the solution temperature kept at 35.degree. C., whereby the
copolymer was saponified. As the saponification proceeded, a
saponification product was precipitated. When the saponification
product was obtained in a particulate form, the saponification
product was filtered out. The resulting saponification product was
thoroughly rinsed with methanol, and dried in a hot air dryer.
Thus, an intended 1,2-diol-containing PVA resin (3) was
prepared.
[0152] The 1,2-diol-containing PVA resin (3) thus prepared had a
saponification degree of 88.0 mol % as determined by measuring an
alkali consumption required for hydrolysis of remaining vinyl
acetate and 3,4-diacetoxy-1-butene. Further, the PVA resin (3) had
an average polymerization degree of 450 as determined by analysis
in conformity with JIS K6726, and a 1,2-diol structural unit
content of 12 mol %.
[0153] Measurement was performed on the thus prepared
1,2-diol-containing PVA resin (3) by means of a differential
scanning calorimeter, and it was found that the 1,2-diol-containing
PVA resin (3) was an amorphous polymer having no melting point peak
without heat of fusion. In the same manner as in Example 1, the
resin was kneaded by means of a twin screw extruder, and formed
into a strand-shaped support material, which was in turn
evaluated.
[0154] The Evaluation Results are also Shown in Table 1.
TABLE-US-00001 TABLE 1 Comparative Example 1 Example 2 Example 1
PVA resin Type of PVA PVA (1) PVA (2) PVA (3) Amount (mol %) 7.2
4.5 12 of 1,2-diol Polymerization 360 450 450 degree Saponification
degree 99 78 88 (mol %) .DELTA.H (J/g) 21.5 14.3 N.D. Acid-modified
SEBS Not contained Not contained Not contained Evaluation Shape
stability .smallcircle..smallcircle. .smallcircle. x Adhesiveness
to model 410 mN/15 mm 160 mN/15 mm 30 mN/15 mm material
[0155] As apparent from the above results, the support materials
each including a 1,2-diol-containing PVA resin having a heat
.DELTA.H of fusion falling within the specific range are more
excellent in shape stability and more useful, with an adhesive
force of higher than 100 mN/15 mm with respect to the model
material, than the support material (Comparative Example 1)
including a 1,2-diol-containing PVA resin having a heat .DELTA.H of
fusion falling outside the specific range.
Example 3
[0156] First, 70 parts of the 1,2-diol-containing PVA resin (1)
prepared in Example 1 and 30 parts of a styrene/ethylene/butylene
block copolymer (SEBS) having a carboxyl group (TOUGHTECH M1911
available from Asahi Kasei Corporation and having an acid value of
2 mg CH.sub.3ONa/g) as a block copolymer were dry-blended. Then,
the resulting mixture was fed into a twin screw extruder and
melt-kneaded. The resulting resin composition was extruded into a
strand having a diameter of 1.75 mm, and the strand was cooled on a
belt with air and wound around a reel. Thus, a support material was
produced, and evaluated in the aforementioned manner. The results
of the evaluation are shown in Table 2.
Example 4
[0157] First, 70 parts of the 1,2-diol-containing PVA resin (2)
prepared in Example 2 and 30 parts of a styrene/ethylene/butylene
block copolymer (SEBS) having a carboxyl group (TOUGHTECH M1911
available from Asahi Kasei Corporation and having an acid value of
2 mg CH.sub.3ONa/g) as a block copolymer were dry-blended. Then, a
support material was produced and evaluated in the same manner as
in Example 3.
[0158] The results of the evaluation are shown in Table 2.
TABLE-US-00002 TABLE 2 Example 3 Example 4 PVA resin Type of PVA
PVA (1) PVA (2) Amount (mol %) of 1,2-diol 7.2 4.5 Polymerization
degree 360 450 Saponification degree (mol %) 99 78 .DELTA.H (J/g)
21.5 14.3 Acid-modified SEBS Contained Contained Evaluation Shape
stability .smallcircle..smallcircle. .smallcircle. Adhesiveness to
model material 560 mN/15 mm 630 mN/15 mm
[0159] As apparent from the above results, the support materials
each including a 1,2-diol-containing PVA resin having a heat
.DELTA.H of fusion falling within the specific range are excellent
in shape stability and useful with an adhesive force of higher than
300 mN/15 mm with respect to the model material.
Examples of Embodiment (Y)
Example 5
(i) Preparation of PVA Resin (5)
[0160] In a reaction can provided with a reflux condenser, a
dropping funnel and a stirrer, 100 parts of vinyl acetate and 100
parts of methanol were first fed, and 0.15 mol % (with respect to
the amount of the fed vinyl acetate) of azobisisobutyronitrile was
fed. Then, the temperature was raised while the resulting mixture
was stirred in a nitrogen stream, thereby initiating
polymerization. After a lapse of 5 hours from the initiation of the
polymerization, 0.05 mol % of azobisisobutyronitrile was added to
the reaction can. When the polymerization degree of vinyl acetate
reached 85%, a predetermined amount of m-dinitrobenzene was added
to the reaction can to terminate the polymerization. Subsequently,
methanol vapor was blown into the reaction can to be distilled,
whereby unreacted vinyl acetate monomer was removed out of the
reaction can. Thus, a copolymer was prepared in the form of a
methanol solution.
[0161] Subsequently, the solution was further diluted with methanol
to a concentration of 50 wt. %, and fed into a kneader. Then, a
methanol solution of sodium hydroxide having a sodium concentration
of 2 wt. % was added in a proportion of 4.3 mmol based on 1 mol of
a vinyl acetate structural unit of the copolymer with the solution
temperature kept at 35.degree. C., whereby the copolymer was
saponified. As the saponification proceeded, a saponification
product was precipitated. When the saponification product was
obtained in a particulate form, 1.0 equivalent of sodium hydroxide
containing acetic acid for neutralization was added to the reaction
can. Then, the resulting saponification product was filtered out,
thoroughly rinsed with methanol, and dried in a hot air dryer.
Thus, an intended PVA resin (5) was prepared.
[0162] The PVA resin (5) thus prepared had a saponification degree
of 88 mol % as determined by measuring an alkali consumption
required for hydrolysis of remaining vinyl acetate, and an average
polymerization degree of 500 as determined by analysis in
conformity with JIS K6726.
(ii) Production of Support Material
[0163] First, 70 parts of the PVA resin (5) and 30 parts of a
styrene/ethylene/butylene block copolymer (SEBS) having a
carboxylic acid group (TOUGHTECH M1911 available from Asahi Kasei
Corporation and having an acid value of 2 mg CH.sub.3ONa/g) as a
block polymer were dry-blended. Then, the resulting mixture was fed
into a twin screw extruder, and melt-kneaded under the following
conditions. The resulting resin composition was extruded into a
strand having a diameter of 1.75 mm, and the strand was cooled on a
belt with air and wound around a reel. Thus, a support material was
produced, and evaluated in the aforementioned manner. The results
of the evaluation are shown in Table 3. Extruder: Available from
Technovel Corporation, and having a diameter of 15 mm and an L/D
ratio of L/D=60
Extruding temperature: C1/C2/C3/C4/C5/C6/C7/C8/D=150.degree.
C./170.degree. C./180.degree. C./190.degree. C./200.degree.
C./210.degree. C./22.degree. C./22.degree. C./220.degree. C.
Rotation speed: 200 rpm Discharge amount: 1.5 kg/hour
(iii) Evaluation of Support Material
[Peelability]
[0164] It is important that the support material is not torn off
even if being stretched for peeling thereof. It is considered that
a support material having a higher breaking stress has a higher
toughness.
[0165] After the laminate shaping with the use of the support
material, the support material is peeled off from a shaped product
of a model material. Without sufficient flexibility, however, the
support material cannot be properly peeled off from the shaped
product of the model material. Without sufficient toughness, the
support material will be torn off when being stretched for peeling
thereof. Therefore, the support material cannot be efficiently
peeled off. Thus, the support material is required to have
flexibility and toughness for proper peelability. For this reason,
flexibility evaluation and toughness evaluation were performed in
the following manner:
<Flexibility Evaluation>
[0166] A strand of the support material maintained in a dry state
was cut to 30 cm, and bent around a cylindrical iron rod having a
diameter of 5 cm with a 10-cm long end portion thereof left. It was
checked whether or not the strand was broken until it was wound
around the rod once. This operation was performed on 5 strands, and
the support material was evaluated based on the following
criteria:
Good (o): Not more than 1 strand was broken. Acceptable (.DELTA.):
2 to 4 strands were broken. Unacceptable (x): All the 5 strands
were broken.
[0167] <Toughness Evaluation>
[0168] A strand of the support material maintained in a dry state
was cut to 10 cm, and a tensile test was performed on the cut
strand by means of a tensile tester by stretching the strand at a
stretching speed of 10 mm/min with a gage distance of 30 mm. At
this time, the breaking stress was determined.
[0169] [Forming Stability]
[0170] The diameters of the produced strand were measured at ten
points spaced 20 cm from each other by means of a caliper, and an
average strand diameter was calculated. Where the cross section of
the strand was not a perfect circle, the greatest diameter was
measured. The strand was evaluated based on the following criteria
indicating the relationship between the calculated average diameter
and the diameters measured at 10 points.
Excellent (oo): All the measured diameters fell within a range of
the average diameter .+-.0.05 mm. Good (o): One or more of the
measured diameters fell outside the range of the average diameter
.+-.0.05 mm, and all the measured diameters fell within a range of
the average diameter .+-.0.15 mm. Acceptable (.DELTA.): One or more
of the measured diameters fell outside the range of the average
diameter .+-.0.15 mm, and all the measured diameters fell within a
range of the average diameter .+-.0.25 mm. Unacceptable (x): One or
more of the measured diameters fell outside the range of the
average diameter .+-.0.25 mm.
[0171] The support material is extruded in a melted state from a
nozzle for shaping. If the diameter of the support material
extruded from the nozzle is unstable, however, the shaping is not
stabilized, making it impossible to shape an intended product with
higher reproducibility. Since the strand of the support material is
formed by extrusion in the melted state, the stable diameter of the
strand means that the support material is stably extruded in the
laminate shaping. Therefore, the support material that ensures the
production of the shaped product with higher reproducibility is
excellent in forming stability in the production of the strand with
a stable strand diameter.
[0172] [Smoothness of Strand]
[0173] The surface of the strand of the support material prepared
in the aforementioned manner was visually and tactilly evaluated
based on the following criteria:
Excellent (oo): The surface was smooth, and free from tackiness.
Good (o): The surface was smooth and tacky. Acceptable (.DELTA.):
The surface was slightly rough and tacky. Unacceptable (x): The
surface was very rough.
Example 6
[0174] A PVA resin (6) having a saponification degree of 72 mol %
was prepared in substantially the same manner as in Example 5 by
reducing the saponification period. Then, a support material was
produced and evaluated in the same manner.
Example 7
[0175] A support material was produced in substantially the same
manner as in Example 5, except that 85 parts of the PVA resin (5)
and 15 parts of the block copolymer were kneaded and extruded.
Then, the support material was evaluated in the same manner.
Example 8
[0176] The support material was produced in substantially the same
manner as in Example 7, except that 15 parts of TOUGHTECH M1913
(available from Asahi Kasei Corporation and having an acid value of
10 mg CH.sub.3ONa/g) was used as the block copolymer.
Example 9
(i) Preparation of 1,2-Diol-Containing PVA Resin (7)
[0177] In a reaction can provided with a reflux condenser, a
dropping funnel and a stirrer, 68.0 parts of vinyl acetate, 23.8
parts of methanol and 8.2 parts of 3,4-diacetoxy-1-butene were
first fed, and then 0.3 mol % (with respect to the amount of the
fed vinyl acetate) of azobisisobutyronitrile was fed. In turn, the
temperature was raised while the resulting mixture was stirred in a
nitrogen stream, thereby initiating polymerization. When the
polymerization degree of vinyl acetate reached 90%, a predetermined
amount of m-dinitrobenzene was added to the reaction can to
terminate the polymerization. Subsequently, methanol vapor was
blown into the reaction can, whereby unreacted vinyl acetate
monomer was removed out of the reaction can. Thus, a copolymer was
prepared in the form of a methanol solution.
[0178] Then, the methanol solution was further diluted with
methanol to a concentration of 55 wt. %, and fed into a kneader.
Then, a methanol solution of sodium hydroxide having a sodium
concentration of 2 wt. % was added in a proportion of 3.5 mmol
based on a total amount of 1 mol of a vinyl acetate structural unit
and a 3,4-diacetoxy-1-butene structural unit of the copolymer with
the solution temperature kept at 35.degree. C., whereby the
copolymer was saponified. As the saponification proceeded, a
saponification product was precipitated. When the saponification
product was obtained in a particulate form, the saponification
product was separated by a solid/liquid separation process. The
resulting saponification product was thoroughly rinsed with
methanol, and dried in a hot air dryer. Thus, an intended
1,2-diol-containing PVA resin (7) was prepared.
[0179] The 1,2-diol-containing PVA resin (7) thus prepared had a
saponification degree of 88.0 mol %, and a polymerization degree of
450. The content of the 1,2-diol structural unit represented by the
above formula was 6 mol % as calculated from an integration value
measured by .sup.1H-NMR (300 MHz proton NMR using a d6-DMSO
solution and an internal standard of tetramethylsilane at
50.degree. C.)
[0180] A support material was produced in substantially the same
manner as in Example 5, except that the 1,2-diol-containing PVA
resin (7) was used instead of the PVA resin (5). Then, the support
material was evaluated.
Example 10
(i) Preparation of 1,2-Diol-Containing PVA Resin (8)
[0181] In a reaction can provided with a reflux condenser, a
dropping funnel and a stirrer, 85 g of vinyl acetate (equivalent to
an initial feed amount of 10 wt. % of the total feed amount), 460 g
of methanol and 13.6 g (7.2 mol % with respect to the amount of the
fed vinyl acetate) of 3,4-diacetoxy-1-butene were first fed, and
then 0.2 mol % (with respect to the amount of the fed vinyl
acetate) of azobisisobutyronitrile was fed. In turn, the
temperature was raised while the resulting mixture was stirred in a
nitrogen stream, thereby initiating polymerization. After a lapse
of 0.5 hours from the initiation of the polymerization, vinyl
acetate (90 wt. % of the total feed amount) was added dropwise to
the reaction can (at a dropping speed of 95.6 g/hr) in 8 hours.
After lapses of 2.5 hours and 4.5 hours from the initiation of the
polymerization, 0.1 mol % of azobisisobutyronitrile was added to
the reaction can. When the polymerization degree of vinyl acetate
reached 85%, a predetermined amount of m-dinitrobenzene was added
to the reaction can to terminate the polymerization. Subsequently,
methanol vapor was blown into the reaction can to be distilled,
whereby unreacted vinyl acetate monomer was removed out of the
reaction can. Thus, a copolymer was prepared in the form of a
methanol solution.
[0182] Then, the methanol solution was further diluted with
methanol to a concentration of 50 wt. %, and fed into a kneader.
Then, a methanol solution of sodium hydroxide having a sodium
concentration of 2 wt. % was added in a proportion of 9 mmol based
on a total amount of 1 mol of a vinyl acetate structural unit and a
3,4-diacetoxy-1-butene structural unit of the copolymer with the
solution temperature kept at 35.degree. C., whereby the copolymer
was saponified. As the saponification proceeded, a saponification
product was precipitated. When the saponification product was
obtained in a particulate form, the 2 wt. % sodium hydroxide
methanol solution was added in a proportion of 4 mmol based on a
total amount of 1 mol of the vinyl acetate structural unit and the
3,4-diacetoxy-1-butene structural unit, whereby the saponification
further proceeded. Thereafter, acetic acid was added in an amount
of 0.8 equivalents based on the amount of the sodium hydroxide for
neutralization. Then, the resulting saponification product was
filtered off, thoroughly rinsed with methanol, and dried in a hot
air dryer. Thus, an intended PVA resin (8) was prepared.
[0183] The PVA resin (8) thus prepared had a saponification degree
of 99.0 mol % as determined by analysis of an alkali consumption
required for hydrolysis of remaining vinyl acetate and
3,4-diacetoxy-1-butene. Further, the PVA resin (8) had an average
polymerization degree of 360 as measured by analysis in conformity
with JIS K6726, and a 1,2-diol structural unit content of 7.2 mol
%.
[0184] A support material was produced in substantially the same
manner as in Example 5, except that the 1,2-diol-containing PVA
resin (8) prepared in the aforementioned manner was used instead of
the PVA resin (5). Then, the support material was evaluated.
Example 11
[0185] A support material was produced by feeding 66.5 parts of the
1,2-diol-containing PVA resin (8) prepared in Example 10, 28.5
parts of the carboxyl group-containing SEBS used in Example 5 and 5
parts of ultrafine talc SG-95 (having a particle diameter of 2.5 m)
available from Nippon Talc Co., Ltd. as a filler into a twin screw
extruder. Then, the support material was evaluated.
Example 12
[0186] A support material was produced in substantially the same
manner as in Example 11, except that 56 parts of the
1,2-diol-containing PVA resin (8), 24 parts of the carboxyl
group-containing SEBS and 20 parts of talc (filler) were used.
Then, the support material was evaluated.
Comparative Example 2
[0187] A support material was produced in substantially the same
manner as in Example 5, except that a carboxyl group-free SEBS
(TOUGHTECH H1041 available from Asahi Kasei Corporation and having
an acid value of 0 mg CH.sub.3ONa/g) provided instead of the block
copolymer of Example 5 and the PVA resin (5) were fed into a twin
screw extruder and melt-kneaded. Then, the support material was
evaluated in the same manner.
[0188] The results of the evaluation are also shown below in Table
3.
TABLE-US-00003 TABLE 3 Example Example Example Comparative Example
5 Example 6 Example 7 Example 8 Example 9 10 11 12 Example 2
Support material PVA resin Side chain 1,2-diol amount (mol %) 0 0 0
0 6 7.2 7.2 7.2 0 Polymerization degree 500 500 500 500 450 360 360
360 500 Saponification degree (mol %) 88 72 88 88 88 99 99 99 88
Proportion (parts) 70 70 85 85 70 70 66.5 56 70 Block copolymer
Proportion (parts) 30 30 15 15 30 30 28.5 24 30 Acid value 2 2 2 10
2 2 2 2 0 Filler Proportion (parts) 0 0 0 0 0 0 5 20 0 Evaluation
Peelability Flexibility .smallcircle. .smallcircle. .DELTA. .DELTA.
.smallcircle. .smallcircle. .smallcircle. .DELTA. x Toughness
N/mm.sup.2 46 44 58 62 72 64 60 43 12 Forming stability Strand
diameter stability .DELTA. .DELTA. .smallcircle. .smallcircle.
.smallcircle..smallcircle. .smallcircle..smallcircle.
.smallcircle..smallcircle. .smallcircle..smallcircle. x Smoothness
of strand Surface state of strand .smallcircle. .DELTA.
.smallcircle. .smallcircle. .smallcircle. .smallcircle.
.smallcircle..smallcircle. .smallcircle..smallcircle. .DELTA.
[0189] As apparent from the above results, the support materials
each including a PVA resin and a block copolymer including a
polymer block of an aromatic vinyl compound and a polymer block of
a conjugated diene compound and/or a block of a hydrogenated
conjugated diene compound and having a functional group reactive
with a hydroxyl group are more excellent in peelability and forming
stability, and more useful for fusion laminate shaping than the
support material (Comparative Example 2) including a PVA resin and
a block copolymer having no functional group reactive with a
hydroxyl group.
[0190] While specific forms of the embodiments of the present
invention have been shown in the aforementioned inventive examples,
the inventive examples are merely illustrative of the invention but
not limitative of the invention. It is contemplated that various
modifications apparent to those skilled in the art could be made
within the scope of the invention.
[0191] The inventive laminate shaping support materials are
excellent in shape stability, adhesiveness to a model material,
peelability and forming stability, and can be advantageously used
as support materials for the fusion laminate shaping process.
* * * * *