U.S. patent application number 10/558758 was filed with the patent office on 2007-01-25 for adhesive composition, process for producing the same, molded objects, and process for producing heat-shrinkable tube.
Invention is credited to Hiroshi Hayami, Kiyoaki Moriuchi, Shinya Nishikawa.
Application Number | 20070020413 10/558758 |
Document ID | / |
Family ID | 34067386 |
Filed Date | 2007-01-25 |
United States Patent
Application |
20070020413 |
Kind Code |
A1 |
Moriuchi; Kiyoaki ; et
al. |
January 25, 2007 |
Adhesive composition, process for producing the same, molded
objects, and process for producing heat-shrinkable tube
Abstract
An adhesive composition comprising 100 parts by weight of a
fluorine-containing polymer and 2 to 30 parts by weight of an
unsaturated compound containing at least one polar group selected
from the group consisting of an epoxy group and a carboxyl group,
wherein the fluorine-containing polymer has been graft-modified
with the polar group-containing unsaturated compound by irradiation
of ionizing radiation, a production process thereof, and formed
products such as a heat-shrinkable tube equipped with a layer
composed of the adhesive composition.
Inventors: |
Moriuchi; Kiyoaki; (Osaka,
JP) ; Hayami; Hiroshi; (Osaka, JP) ;
Nishikawa; Shinya; (Osaka, JP) |
Correspondence
Address: |
MCDERMOTT WILL & EMERY LLP
600 13TH STREET, N.W.
WASHINGTON
DC
20005-3096
US
|
Family ID: |
34067386 |
Appl. No.: |
10/558758 |
Filed: |
July 14, 2004 |
PCT Filed: |
July 14, 2004 |
PCT NO: |
PCT/JP04/10350 |
371 Date: |
December 1, 2005 |
Current U.S.
Class: |
428/34.9 |
Current CPC
Class: |
C09J 151/003 20130101;
C09J 151/06 20130101; B65D 41/24 20130101; C08L 2666/24 20130101;
C09J 151/003 20130101; C09J 151/003 20130101; Y10T 428/1328
20150115; C08L 51/003 20130101; C08L 2666/02 20130101; C08F 259/08
20130101; C08L 2666/02 20130101; C08L 51/003 20130101; C08L 51/003
20130101; C08L 2666/02 20130101; C08L 2666/24 20130101; C08L
2666/24 20130101; C08L 2666/02 20130101; C09J 151/06 20130101 |
Class at
Publication: |
428/034.9 |
International
Class: |
F16B 4/00 20060101
F16B004/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 14, 2003 |
JP |
2003-274333 |
Mar 26, 2004 |
JP |
2004-091662 |
Claims
1. An adhesive composition comprising 100 parts by weight of a
fluorine-containing polymer and 2 to 30 parts by weight of an
unsaturated compound containing at least one polar group selected
from the group consisting of an epoxy group and a carboxyl group,
wherein the fluorine-containing polymer has been graft-modified
with the polar group-containing unsaturated compound by irradiation
of ionizing radiation.
2. The adhesive composition according to claim 1, which further
comprises an antioxidant in a proportion of 0.1 to 5 parts by
weight per 100 parts by weight of the fluorine-containing
polymer.
3. The adhesive composition according to claim 1, wherein the
fluorine-containing polymer is at least one polymer selected from
the group consisting of a fluororesin and a fluororubber.
4. The adhesive composition according to claim 3, wherein the
fluororesin is a fluororesin having a melting point not lower than
80.degree. C., but lower than 140.degree. C., and the fluororubber
is a fluororubber having a Mooney viscosity (ML.sub.1+10,
121.degree. C.) of 5 to 70.
5. The adhesive composition according to claim 3, wherein the
fluororesin is at least one fluororesin selected from the group
consisting of polyvinylidene fluoride (PVdF), binary copolymers
(VdF-TFE copolymers) of vinylidene fluoride (VdF) and
tetrafluoroethylene (TFE), binary copolymers (VdF-HFP copolymers)
of vinylidene fluoride (VdF) and hexafluoropropylene (HFP), ternary
copolymers (VdF-TFE-HFP terpolymers) of vinylidene fluoride (VdF),
tetrafluoroethylene (TFE) and hexafluoropropylene (HFP), copolymers
(ETFEs) of ethylene and tetrafluoroethylene (TFE), copolymers
(ECTFEs) of ethylene and chlorotrifluoroethylene (CTFE), copolymers
(FEPs) of tetrafluoroethylene (TFE) and hexafluoropropylene (HFP),
and copolymers (PFAs) of tetrafluoroethylene (TFE) and a
perfluoroalkyl vinyl ether.
6. The adhesive composition according to claim 3, wherein the
fluororubber is at least one fluororubber selected from the group
consisting of copolymer rubber (VdF-HFP fluororubber) of vinylidene
fluoride (VdF) and hexafluoropropylene (HFP), terpolymer rubber
(VdF-HFP-TFE fluororubber) of vinylidene fluoride (VdF),
hexafluoropropylene (HFP) and tetrafluoroethylene (TFE), copolymer
rubber (VdF-PFP fluororubber) of vinylidene fluoride (VdF) and
pentafluoropropylene (PFP), terpolymer rubber (VdF-PFP-TFE
fluororubber) of vinylidene fluoride (VdF), pentafluoropropylene
(PFP) and tetrafluoroethylene (TFE), terpolymer rubber
(VdF-PFMVE-TFE fluororubber) of vinylidene fluoride (VdF),
perfluoromethyl vinyl ether (PFMVE) and tetrafluoroethylene (TFE),
copolymer rubber (VdF-CTFE fluororubber) of vinylidene fluoride
(VdF) and chlorotrifluoroethylene (CTFE), copolymer rubber (TFE-P
fluororubber) of tetrafluoroethylene (TFE) and propylene (P), and
thermoplastic fluororubber.
7. The adhesive composition according to claim 1, wherein the epoxy
group-containing unsaturated compound is a compound having at least
one epoxy group and a polymerizable carbon-carbon unsaturated bond
in a chemical structure thereof.
8. The adhesive composition according to claim 7, wherein the epoxy
group-containing unsaturated compound is at least one compound
selected from the group consisting of glycidyl esters of
unsaturated carboxylic acids, allylglycidyl isocyanates,
monoglycidyl or polyglycidyl esters of unsaturated polycarboxylic
acids, and allyl glycidyl ethers.
9. The adhesive composition according to claim 8, wherein the
glycidyl ester of the unsaturated carboxylic acid is glycidyl
methacrylate, and the allylglycidyl isocyanate is
diallylmonoglycidyl isocyanate.
10. The adhesive composition according to claim 1, wherein the
carboxyl group-containing unsaturated compound is a compound having
at least one carboxyl group or acid anhydride group and a
polymerizable carbon-carbon double bond in a chemical structure
thereof.
11. The adhesive composition according to claim 10, wherein the
carboxyl group-containing unsaturated compound is at least one
compound selected from the group consisting of unsaturated
carboxylic acids, anhydrides of unsaturated dicarboxylic acids, and
anhydrides of unsaturated carboxylic acids.
12. The adhesive composition according to claim 11, wherein the
acid anhydride of the unsaturated dicarboxylic acid is maleic
anhydride.
13. The adhesive composition according to claim 1, wherein the
fluorine-containing polymer has been graft-modified with the polar
group-containing unsaturated compound by irradiation of ionizing
radiation in the quantity of 20 to 700 kGy.
14. The adhesive composition according to claim 1, which exhibits
initial adhesion strength of at least 1.0 kg/cm to any of a
stainless steel plate, a copper plate, an iron plate and an
aluminum plate when a strip sample formed from the adhesive
composition and having a thickness of 1 mm is laminated on a metal
plate selected from the group consisting of the stainless steel
plate, copper plate, iron plate and aluminum plate, and the
laminated sample is then subjected to a T-shape peeling test at a
rate of pulling of 50 mm/min.
15. The adhesive composition according to claim 1, which exhibits
initial adhesion strength of at least 1.0 kg/cm to any of a
stainless steel plate, a copper plate, an iron plate and an
aluminum plate when a strip sample formed from the adhesive
composition and having a thickness of 1 mm is laminated on a metal
plate selected from the group consisting of the stainless steel
plate, copper plate, iron plate and aluminum plate, the laminated
sample is then left to stand for 3,000 hours in a gear oven of
150.degree. C. to accelerate its deterioration, and the sample is
then subjected to a T-shape peeling test at a rate of pulling of 50
mm/min.
16. A formed product on a desired position of which an adhesive
layer composed of the adhesive composition according to any one of
claims 1 to 15 has been arranged.
17. A multi-layer heat-shrinkable tube having a structure that an
adhesive layer composed of the adhesive composition according to
any one of claims 1 to 15 has been arranged on an internal surface
of a heat-shrinkable tube.
18. A heat-shrinkable cap having a structure that an adhesive layer
composed of the adhesive composition according to any one of claims
1 to 4 has been arranged on an internal surface of a
heat-shrinkable tube, and one opening end of the heat-shrinkable
tube has been shrunk by heat shrinkage to seal the end with the
molten adhesive composition.
19. A process for producing an adhesive composition comprising a
fluorine-containing polymer, which comprises the following steps i
and ii: (i) Step i of incorporating 2 to 30 parts by weight of an
unsaturated compound containing at least one polar group selected
from the group consisting of an epoxy group and a carboxyl group
into 100 parts by weight of the fluorine-containing polymer to
prepare a fluorine-containing polymer composition; and (ii) Step ii
of forming the composition into a desired shape as needed, and then
irradiating the composition with ionizing radiation to graft-modify
the fluorine-containing polymer with the polar group-containing
unsaturated compound.
20. A process for producing a multi-layer heat-shrinkable tube
having an adhesive layer on an internal surface thereof, which
comprises the following steps 1 to 4: (1) Step 1 of co-extruding a
radiation-crosslinking composition comprising a fluorine-containing
polymer and a polyfunctional monomer and a fluorine-containing
polymer composition comprising 100 parts by weight of a
fluorine-containing polymer and 2 to 30 parts by weight of an
unsaturated compound containing at least one polar group selected
from the group consisting of an epoxy group and a carboxyl group to
form a tube-like formed product of a 2-layer structure having an
outer layer composed of the radiation-crosslinking composition and
an inner layer composed of the fluorine-containing polymer
composition; (2) Step 2 of irradiating the tube-like formed product
with ionizing radiation to crosslink the radiation-crosslinking
composition of the outer layer and graft-modify the
fluorine-containing polymer composition of the inner layer; (3)
Step 3 of expanding the tube-like formed product in a radial
direction thereof under heating; and (4) Step 4 of cooling the
tube-like formed product to fix the form expanded in the radial
direction.
Description
TECHNICAL FIELD
[0001] The present invention relates to an adhesive composition
that can be hot-melted and is excellent in adhesive property to
metallic adherends and heat resistance, and formed products on
which an adhesive layer composed of the adhesive composition has
been arranged. Of the formed products are representative
multi-layer heat-shrinkable tubes and heat-shrinkable caps of a
structure that the adhesive layer has been arranged on internal
surfaces thereof. The present invention also relates to production
processes of the adhesive composition and multi-layer
heat-shrinkable tubes.
[0002] The adhesive composition, and multi-layer heat-shrinkable
tubes and heat-shrinkable caps according to the present invention
can be suitably applied to protection of electric wires, wire
harnesses and pipes, of which high heat resistance that a
continuous service temperature is at least 150.degree. C. is
required, and hermetic sealing of joints and ends.
BACKGROUND ART
[0003] Respective members such as electric wires, wire harnesses
and pipes, which are arranged in automobiles, aerospace equipments
or the like, are used under a high-temperature environment, so that
adhesive materials used in protection, connection, hermetic sealing
or the like thereof are required to have high heat resistance that
a continuous service temperature is at least 150.degree. C.
[0004] For example, a heat-shrinkable tube, on the internal surface
of which a hot-melt adhesive layer has been arranged, is used in
binding and connection of wire harnesses used in an automobile, or
protection of a branched portion from the viewpoints of insulating
property and waterproofness. The heat-shrinkable tube, on the
internal surface of which the hot-melt adhesive layer has been
arranged, is also used for improving the anticorrosion of a
hydraulic piping composed of copper, iron, stainless steel or the
like and the waterproofness of a joint.
[0005] In the heat-shrinkable tube, on the internal surface of
which the hot-melt adhesive layer has been arranged, the hot-melt
adhesive is melted to be filled in a space between the surface of
an adherend and the heat-shrinkable tube and bonded to the adherend
when the heat-shrinkable tube is heated and shrunk to bring it into
close contact with the periphery of the adherend, whereby
penetration of water and corrosive gases from an end of the
heat-shrinkable tube is prevented, thereby exhibiting
waterproofness and anticorrosion.
[0006] As a material for forming a heat-shrinkable tube body, has
heretofore been used, for example, polystyrene, polyvinyl chloride,
crosslinked polyethylene, fluororesin or fluororubber. A
heat-shrinkable tube composed of a fluorine-containing polymer such
as a fluororesin or fluororubber is generally used in uses of which
high heat resistance that a continuous service temperature is at
least 150.degree. C. is required.
[0007] Adhesive compositions comprising, as a principal component,
a polyamide resin such as a dimer acid type polyamide resin,
polyamide 6, polyamide 10 or polyamide 11 are representative of the
hot-melt adhesive arranged on the internal surface of the
heat-shrinkable tube. These hot-melt adhesives are coated on the
internal surface of the heat-shrinkable tube. However, the
continuous service temperature of these hot-melt adhesives is at
most about 105.degree. C., so that they cannot be applied to uses
of which high heat resistance that a continuous service temperature
is at least 150 is required. In other words, when a conventional
heat-shrinkable tube is held for a long period of time under
high-temperature conditions of at least 150.degree. C. in a state
that it has been brought into close contact with the periphery of
an adherend, its adhesion strength to the adherend is lowered.
[0008] There has heretofore been proposed a heat-shrinkable tube of
a 2-layer structure that a layer of a fluororesin composition
having a low melting point and high flowability is arranged on an
internal surface of a crosslinked heat-shrinkable tube composed of
a fluororesin (Japanese Patent Application Laid-Open No. 5-57791).
According to this heat-shrinkable tube, the fluororesin composition
of the internal layer can be melted upon the shrinkage under
heating to be filled in a space between an adherend and the
heat-shrinkable tube. However, the fluororesin composition does not
have adhesive property, so that the heat-shrinkable tube may not be
satisfactory in that the function of being bonded to the adherend
to improve waterproofness and anticorrosion is exhibited.
DISCLOSURE OF THE INVENTION
[0009] It is an object of the present-invention to provide an
adhesive composition that can be hot-melted and is excellent in
adhesive property to various adherends such as metallic adherends
(including adherends having a metallic surface layer) and heat
resistance.
[0010] Another object of the present invention is to provide a
formed product on which an adhesive layer composed of an adhesive
composition that can be hot-melted and is excellent in adhesive
property to various adherends including metallic adherends and heat
resistance has been arranged.
[0011] A particular object of the present invention is to provide a
multi-layer heat-shrinkable tube and a multi-layer heat-shrinkable
cap of a structure that an adhesive layer composed of an adhesive
composition excellent in adhesive property to various adherends
including metallic adherends and heat resistance has been arranged
on internal surfaces thereof.
[0012] A further object of the present invention is to provide
production processes of the adhesive composition and multi-layer
heat-shrinkable tube.
[0013] The present inventors have carried out an extensive
investigation with a view toward achieving the above objects. As a
result, it has been found that an unsaturated compound containing
at least one polar group selected from the group consisting of an
epoxy group and a carboxyl group is incorporated into a
fluorine-containing polymer such as a fluororesin or fluororubber,
and the resultant fluorine-containing polymer composition is
irradiated with ionizing radiation to graft-modify the
fluorine-containing polymer with the polar group-containing
unsaturated compound, thereby providing an adhesive composition
that can be hot-melted, is excellent in adhesive property to
various adherends including metallic adherends and has high heat
resistance that a continuous service temperature is at least
150.degree. C.
[0014] The adhesive composition according to the present invention
can be arranged as an adhesive layer on a desired position of a
formed product such as a heat-shrinkable tube. In particular, a
heat-shrinkable tube of a multi-layer structure that a layer of the
adhesive composition has been formed on an internal surface of a
heat-shrinkable rube formed from a radiation-crosslinking
composition comprising a fluorine-containing polymer and a
polyfunctional monomer permits hot-melting the adhesive composition
under heating conditions for heat shrinkage to be filled in a space
between an adherend and the heat-shrinkable tube and moreover is
excellent in adhesive property of the adhesive composition to the
adherend, so that it can markedly improve the waterproofness and
anticorrosion of various adherends including metallic
adherends.
[0015] One opening end of the heat-shrinkable tube having such a
layer structure is heat-shrunk to form a structure that the end has
been sealed with the molten adhesive composition, whereby a
heat-shrinkable cap can be provided. The heat-shrinkable cap
according to the present invention may be suitably used in hermetic
sealing of end portions of electric wires, wire harnesses or the
like.
[0016] The present invention has been led to completion on the
basis of these findings.
[0017] According to the present invention, there is thus provided
an adhesive composition comprising 100 parts by weight of a
fluorine-containing polymer and 2 to 30 parts by weight of an
unsaturated compound containing at least one polar group selected
from the group consisting of an epoxy group and a carboxyl group,
wherein the fluorine-containing polymer has been graft-modified
with the polar group-containing unsaturated compound by irradiation
of ionizing radiation.
[0018] According to the present invention, there is also provided a
formed product on a desired position of which an adhesive layer
composed of the above-described adhesive composition has been
arranged. According to the present invention, there is particularly
provided a multi-layer heat-shrinkable tube having a structure that
an adhesive layer composed of the above-described adhesive
composition has been arranged on an internal surface of a
heat-shrinkable tube.
[0019] According to the present invention, there is further
provided a heat-shrinkable cap having a structure that an adhesive
layer composed of the above-described adhesive composition has been
arranged on an internal surface of a heat-shrinkable tube, and one
opening end of the heat-shrinkable tube has been shrunk by heat
shrinkage to seal the end with the molten adhesive composition.
[0020] According to the present invention, there is still further
provided a process for producing an adhesive composition comprising
a fluorine-containing polymer, which comprises the following steps
i and ii: [0021] (i) Step i of incorporating 2 to 30 parts by
weight of an unsaturated compound containing at least one polar
group selected from the group consisting of an epoxy group and a
carboxyl group into 100 parts by weight of the fluorine-containing
polymer to prepare a fluorine-containing polymer composition; and
[0022] (ii) Step ii of forming the composition into a desired shape
as needed, and then irradiating the composition with ionizing
radiation to graft-modify the fluorine-containing polymer with the
polar group-containing unsaturated compound.
[0023] According to the present invention, there is yet still
further provided a process for producing a multi-layer
heat-shrinkable tube having an adhesive layer on an internal
surface thereof, which comprises the following steps 1 to 4: [0024]
(1) Step 1 of co-extruding a radiation-crosslinking composition
comprising a fluorine-containing polymer and a polyfunctional
monomer and a fluorine-containing polymer composition comprising
100 parts by weight of a fluorine-containing polymer and 2 to 30
parts by weight of an unsaturated compound containing at least one
polar group selected from the group consisting of an epoxy group
and a carboxyl group to form a tube-like formed product of a
2-layer structure having an outer layer composed of the
radiation-crosslinking composition and an inner layer composed of
the fluorine-containing polymer composition; [0025] (2) Step 2 of
irradiating the tube-like formed product with ionizing radiation to
crosslink the radiation-crosslinking composition of the outer layer
and graft-modify the fluorine-containing polymer composition of the
inner layer; [0026] (3) Step 3 of expanding the tube-like formed
product in a radial direction thereof under heating; and [0027] (4)
Step 4 of cooling the tube-like formed product to fix the form
expanded in the radial direction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 schematically illustrates a layer structure of a
multi-layer heat-shrinkable tube according to the present
invention.
[0029] FIG. 2 schematically illustrates a production process of a
heat-shrinkable cap.
[0030] FIG. 3 is a cross-sectional vies illustrating a structure of
a heat-shrinkable cap according to the present invention.
[0031] FIG. 4 schematically illustrates a step of capping an end of
a covered cable with the heat-shrinkable cap.
BEST MODE FOR CARRYING OUT THE INVENTION
1. Adhesive composition
[0032] In the present invention, as a polymer base of an adhesive
composition, is used at least one fluorine-containing polymer
selected from the group consisting of fluororesins and
fluororubbers.
[0033] Examples of the fluororesins include thermoplastic
fluororesins, such as polyvinylidene fluoride (PVdF) that is a
homopolymer of vinylidene fluoride (VdF); binary or ternary PVdF
copolymers (for example, VdF-TFE copolymers, VdF-HFP copolymers,
VdF-TFE-HFP terpolymers) of vinylidene fluoride (VdF) and
tetrafluoroethylene (TFE) and/or hexafluoropropylene (HFP);
copolymers (ETFEs) of ethylene and TFE, and ternary ETFEs with a
third component additionally added thereto; copolymers (ECTFEs) of
ethylene and chlorotrifluoroethylene (CTFE), and ternary ECTFEs
with a third component added thereto; FEPs that are copolymers of
TFE and HFP; and PFAs that are copolymers of TFE and a
perfluoroalkyl vinyl ether such as perfluoromethyl vinyl ether
(PFMVE).
[0034] Examples of the fluororubbers include vinylidene
fluoride-containing fluororubbers (FKMs) (for example, VdF-HFP
fluororubber, VdF-HFP-TFE fluororubber, VdF-PFP fluororubber,
VdF-PFP-TFE fluororubber, VdF-PFMVF-TFE fluororubber, and VdF-CTFE
fluororubber) with vinylidene fluoride (VdF) copolymerized with any
of hexafluoropropylene (HFP), tetrafluoroethylene (TFE),
pentafluoropropylene (PFP), perfluoromethyl vinyl ether (PFMVE) and
chlorotrifluoroethylene (CTFE); and tetrafluoroethylene-propylene
fluororubber (TFE-P) of TFE and propylene, and TFE-P-containing
fluororubbers with a third component added to TFE-P. In addition, a
thermoplastic fluororubber comprising a fluororubber that is a soft
segment and a thermoplastic fluororesin that is a hard segment may
also be used.
[0035] The fluororesins and fluororubbers may be used either singly
or in any combination thereof. A blend of the fluororesin and
fluororubber may be used. When the fluororesin is blended with the
fluororubber, a proportion of both components blended may be
changed within a weight ratio range of preferably from 5:95 to
95:5, more preferably from 10:90 to 90:10. Other thermoplastic
resins, rubbers and thermoplastic elastomers may be blended with
the fluorine-containing polymer, as needed, within limits not
impairing heat resistance and adhesive property.
[0036] In the present invention, an unsaturated compound
(hereinafter abbreviated as "polar group-containing unsaturated
compound") containing at least one polar group selected from the
group consisting of an epoxy group and a carboxyl group is used to
graft-modify the fluorine-containing polymer.
[0037] Examples of the epoxy group-containing unsaturated compounds
include glycidyl esters of unsaturated carboxylic acids, such as
glycidyl acrylate, glycidyl methacrylate and glycidyl
p-styrylcarboxylate; allylglycidyl isocyanates such as
diallylmonoglycidyl isocyanate and monoallyl-diglycidyl isocyanate;
monoglycidyl esters or polyglycidyl esters of unsaturated
polycarboxylic acids, such as
endo-bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylic acid and
endo-cis-bicyclo[2,2,1]hept-5-ene-2-methyl-2,3-dicarboxylic acid;
unsaturated glycidyl ethers (ally glycidyl ethers) such as allyl
glycidyl ether, 2-methylallyl glycidyl ether, glycidyl ether of
o-allylphenol, glycidyl ether of m-allylphenol and glycidyl ether
of p-allylphenol; and 2-(o-vinylphenyl)ethylene oxide,
2-(p-vinylphenyl)ethylene oxide, 2-(o-allylphenyl)ethylene oxide,
2-(p-allylphenyl)ethylene oxide, 2-(o-vinylphenyl)propylene oxide,
2-(p-vinylphenyl)propylene oxide, p-glycidylstyrene,
3,4-epoxy-1-butene, 3,4-epoxy-3-methyl-1-butene,
3,4-epoxy-1-pentene, 3,4-epoxy-3-methyl-1-pentene,
5,6-epoxy-1-hexene, vinylcyclohexane monoxide, and
allyl-2,3-epoxycyclopentyl ether.
[0038] The epoxy group-containing unsaturated compounds are not
limited to the above-described compounds so far as they are
compounds having at least one epoxy group and a polymerizable
carbon-carbon unsaturated bond in their chemical structures.
[0039] Among these epoxy group-containing unsaturated compounds,
glycidyl esters of unsaturated carboxylic acids, allylglycidyl
isocyanates, monoglycidyl or polyglycidyl esters of unsaturated
polycarboxylic acids and allyl glycidyl ethers are preferred in
that graft addition can be conducted at a high rate of reaction by
irradiation of ionizing radiation, with glycidyl esters of
unsaturated carboxylic acids and allylglycidyl isocyanates being
more preferred. Among these, glycidyl methacrylate and
diallylmonoglycidyl isocyanate are particularly preferred. The
epoxy group-containing unsaturated compounds may be used either
singly or in any combination thereof.
[0040] Examples of the carboxyl group-containing unsaturated
compounds include unsaturated carboxylic acids such as acrylic
acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid
and itaconic acid; anhydrides of unsaturated dicarboxylic acids,
such as maleic anhydride, itaconic anhydride and succinic
anhydride; and anhydrides of unsaturated carboxylic acids, such as
crotonic anhydride. Accordingly, the carboxyl group-containing
unsaturated compounds used in the present invention include
unsaturated carboxylic acid derivatives such as acid anhydrides in
addition to unsaturated carboxylic acids. Other unsaturated
carboxylic acid derivatives than the acid anhydrides include
halides, amides, imides and esters of unsaturated carboxylic
acids.
[0041] The carboxyl group-containing unsaturated compounds are not
limited to the above-described compounds so far as they are
compounds having at least one carboxyl group (including acid
anhydride group or the like) and a polymerizable carbon-carbon
unsaturated bond in their chemical structures.
[0042] The carboxyl group-containing unsaturated compounds may be
used either singly or in any combination thereof. Among the
carboxyl group-containing unsaturated compounds, compounds having
an anhydride and a carbon-carbon double bond are preferred in that
graft addition can be conducted at a relatively high rate of
reaction by irradiation of ionizing radiation. Among those
compounds, maleic anhydride is particularly preferred.
[0043] The carboxyl group-containing unsaturated compound and the
epoxy group-containing unsaturated compound may be used in
combination if desired.
[0044] The polar group-containing unsaturated compound is used in a
proportion of 2 to 30 parts by weight, preferably 2.5 to 25 parts
by weight per 100 parts by weight of the fluorine-containing
polymer. If the proportion of the polar group-containing
unsaturated compound blended is too low or too high, the adhesive
property of the resulting adhesive composition to metals is
deteriorated in any case.
[0045] Examples of the ionizing radiation include electron rays,
.gamma.-rays, X-rays, .alpha.-rays and ultraviolet rays. Electron
rays and .gamma.-rays are preferred from the viewpoints of
transmission thickness of the ionizing radiation and industrial
utilization such as reaction velocity of grafting, with accelerated
electron rays by applying acceleration voltage to conduct
irradiation being particularly preferred.
[0046] The fluorine-containing polymer composition comprising the
fluorine-containing polymer and the unsaturated compound containing
at least one polar group selected from the group consisting of an
epoxy group and a carboxyl group is irradiated with ionizing
radiation to graft the polar group-containing unsaturated compound
on the fluorine-containing polymer. The fluorine-containing polymer
graft-modified can be given adhesive property to metals or the like
and can exhibit melt flowability by heating.
[0047] The quantity of the ionizing radiation irradiated is
preferably within a range of 20 to 700 kGy. If the quantity of the
ionizing radiation irradiated is smaller than 20 kGy, the initial
adhesive property of the resulting adhesive composition is
deteriorated. If the quantity exceeds 700 kGy, decomposition of the
adhesive resin composition becomes marked to impair the heat
resistance of the resulting adhesive composition. It is hence not
preferable to irradiate the polymer composition with the ionizing
radiation in such a too small or too great quantity. The degree of
the graft modification by the polar group-containing unsaturated
compound can be controlled by adjusting the proportion of the polar
group-containing unsaturated compound blended to the
fluorine-containing polymer and the quantity of the ionizing
radiation irradiated.
[0048] Into the adhesive composition, as needed, may be
incorporated fillers such as inorganic fillers, antioxidants,
stabilizers, lubricants, ultraviolet absorbents, light stabilizers,
copper inhibitors, cross linking agents, cross linking aids, cross
linking inhibitors, vulcanizing agents, vulcanization accelerators,
scorch retarders, antiozonants, silicones, plasticizers, softeners,
foaming agents, preservatives, etc.
[0049] An antioxidant is preferably incorporated from the viewpoint
of improving the heat stability of the adhesive composition. As
examples of the antioxidant, may be mentioned
pentaerythritol-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],
tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]metha-
ne, 1,1,3-tris-(2-methyl-4-hydroxy-5-t-butylphenyl)butane,
4,4'-butylidene-bis(3-methyl-6-t-butylphenol), and
tris(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate.
[0050] The antioxidant is used in a proportion of generally 0.1 to
5 parts by weight, preferably 0.2 to 3 parts by weight, more
preferably 0.3 to 2 parts by weight per 100 parts by weight of the
fluorine-containing polymer.
[0051] The fluorine-containing polymer composition comprising the
fluorine-containing polymer and the unsaturated compound containing
at least one polar group selected from the group consisting of an
epoxy group and a carboxyl group is irradiated with the ionizing
radiation. As needed, the fluorine-containing polymer composition
may be preformed into a sheet, film, coating layer (coating film)
or any other form before the irradiation. For example, a film
formed from the fluorine-containing polymer composition is
irradiated with the ionizing radiation, whereby a dry film having
adhesive property can be obtained. Such a dry film may be caused to
act as an adhesive film by interposing it between, for example, a
metallic adherend and another article and heating and pressurizing
them.
[0052] A layer of the fluorine-containing polymer composition is
arranged on an internal surface of a heat-shrinkable tube and
irradiated with the ionizing radiation, whereby a multi-layer
heat-shrinkable tube having the adhesive composition layer having
adhesive property and melt flowability (hot-melt property) is
obtained.
[0053] The process according to the present invention for producing
the adhesive composition comprising the fluorine-containing polymer
comprises the following steps i and ii: [0054] (i) Step i of
incorporating 2 to 30 parts by weight of an unsaturated compound
containing at least one polar group selected from the group
consisting of an epoxy group and a carboxyl group into 100 parts by
weight of the fluorine-containing polymer to prepare a
fluorine-containing polymer composition; and [0055] (ii) Step ii of
forming the composition into a desired shape as needed, and then
irradiating the composition with ionizing radiation to graft-modify
the fluorine-containing polymer with the polar group-containing
unsaturated compound.
[0056] The quantity of the ionizing radiation irradiated is
preferably within the above-described range.
[0057] The initial adhesion strength of the adhesive composition
according to the present invention to a stainless steel plate, a
copper plate, an iron plate and an aluminum plate in "test for
initial adhesion strength to metal plates" by a T-shape peeling
test (rate of pulling: 50 mm/min), which will be described in
Example 1, is at least 1.0 kg/cm in any case, and adhesive strength
to each plate after subjected to accelerated deterioration under
conditions of 3,000 hours in a gear oven of 150.degree. C. is also
at least 1.0 kg/cm. The adhesive composition has a continuous
service temperature of at least 150.degree. C.
2. Formed product
[0058] The formed product according to the present invention is
such that an adhesive layer formed of the adhesive composition
described above is arranged on a desired position of a formed
product. No particular limitation is imposed on the shape and
material of the formed product. However, it is preferably a formed
product of a synthetic resin, more preferably a formed product
composed of a fluorine-containing polymer.
[0059] As specific examples of the formed product, on which the
adhesive layer has been arranged, may be mentioned multi-layer
heat-shrinkable tubes having a structure that an adhesive layer
formed of the adhesive composition described above has been formed
on an internal surface of a heat-shrinkable rube. No particular
limitation is imposed on the heat-shrinkable tube. However, that
obtained by forming a radiation-crosslinking composition comprising
a fluorine-containing polymer and a polyfunctional monomer into a
tube and irradiating the composition with ionizing radiation to
crosslink it is preferred.
[0060] As other specific examples of the formed product, on which
the adhesive layer has been arranged, may be mentioned
heat-shrinkable caps having a structure that an adhesive layer
formed of the adhesive composition described above has been formed
on an internal surface of a heat-shrinkable tube, and one opening
end of the heat-shrinkable tube has been shrunk by heat shrinkage
to seal the end with the molten adhesive composition.
[0061] The process according to the present invention for producing
the multi-layer heat-shrinkable tube having an adhesive layer on an
internal surface thereof comprises the following steps 1 to 4:
[0062] (1) Step 1 of co-extruding a radiation-crosslinking
composition comprising a fluorine-containing polymer and a
polyfunctional monomer and a fluorine-containing polymer
composition comprising 100 parts by weight of a fluorine-containing
polymer and 2 to 30 parts by weight of an unsaturated compound
containing at least one polar group selected from the group
consisting of an epoxy group and a carboxyl group to form a
tube-like formed product of a 2-layer structure having an outer
layer composed of the radiation-crosslinking composition and an
inner layer composed of the fluorine-containing polymer
composition; [0063] (2) Step 2 of irradiating the tube-like formed
product with ionizing radiation to crosslink the
radiation-crosslinking composition of the outer layer and
graft-modify the fluorine-containing polymer composition of the
inner layer; [0064] (3) Step 3 of expanding the tube-like formed
product in a radial direction thereof under heating; and [0065] (4)
Step 4 of cooling the tube-like formed product to fix the form
expanded in the radial direction.
[0066] As the fluorine-containing polymer forming the body (outer
layer) of the heat-shrinkable tube, may be used the same
fluorine-containing polymer as that used for producing the adhesive
composition. Among these polymers, a fluororesin or fluororubber
containing a vinylidene fluoride unit is preferred.
[0067] As examples of such fluororesin or fluororubber, may be
mentioned polyvinylidene fluoride (PVdF) that is a homopolymer of
vinylidene fluoride (VdF); and binary or ternary PVdF copolymers
(for example, VdF-TFE copolymers, VdF-HFP copolymers, VdF-TFE-HFP
terpolymers) of vinylidene fluoride (VdF) and tetrafluoroethylene
(TFE) and/or hexafluoropropylene (HFP). The vinylidene fluoride
unit in the PVdF copolymer is preferably contained in a proportion
of at least 60% by weight, more preferably at least 65% by weight,
particularly preferably at least 70% by weight.
[0068] The polyfunctional monomer is a compound at least 2
polymerizable carbon-carbon double bonds. Specific examples of the
polyfunctional monomer include allyl compounds such as diallyl
phthalate, triallyl cyanurate and triallyl isocyanurate;
methacrylate compounds such as ethylene glycol dimethacrylate,
trimethylolpropane trimethacrylate, trimethylolethane methacrylate,
trimethylolpropane acrylate, trimethylolpropane methacrylate,
trimethylolethane triacrylate and tetramethylolmethane
tetraacrylate; and vinyl compounds such as divinylbenzene.
[0069] Among these polyfunctional monomers, trimethylolpropane
trimethacrylate and triallyl isocyanurate are preferred from the
viewpoints of crosslinking property, heat resistance and
dispersibility in the fluorine-containing polymer.
[0070] The polyfunctional monomers may be used either singly or in
any combination thereof. The polyfunctional monomer may be used in
a proportion of preferably 0.1 to 20 parts by weight, more
preferably 0.3 to 10 parts by weight, particularly preferably 0.5
to 5 parts by weight per 100 parts by weight of the
fluorine-containing polymer.
[0071] As a preferable process for producing the multi-layer
heat-shrinkable tube, a radiation-crosslinking composition (A)
comprising the fluorine-containing polymer and the polyfunctional
monomer and a fluorine-containing polymer composition (B)
comprising the fluorine-containing polymer and the polar
group-containing unsaturated compound are first co-extruded to form
a tube-like formed product of a 2-layer structure having an outer
layer composed of the radiation-crosslinking composition (A) and an
inner layer composed of the fluorine-containing polymer composition
(B)
[0072] The tube-like formed product is then irradiated with
ionizing radiation to crosslink the radiation-crosslinking
composition (A) of the outer layer and graft-modify the
fluorine-containing polymer composition (B) of the inner layer.
Upon the irradiation, irradiation conditions are preferably
controlled in such a manner that the quantity of the ionizing
radiation irradiated on the fluorine-containing polymer composition
(B) of the inner layer falls within a range of 20 to 700 kGy. In
order to crosslink the radiation-crosslinking composition (A) of
the outer layer, it is thus preferable to control the quantity of
the ionizing radiation irradiated within the range of 20 to 700
kGy.
[0073] The tube-like formed product after the irradiation is then
expanded in a radial direction thereof under heating, and cooled in
this state to fix the form. In order to expand the tube-like formed
product after the irradiation, the formed product is generally
expanded to ordinarily 1.1 to 5 times, preferably 1.2 to 4 times,
more preferably 1.3 to 3 times as much as the original diameter
thereof. As a method for expanding the formed product, is
preferably used a method of blowing compressed air into an interior
cavity of the tube-like formed product. The cooling and fixation
after the expansion is conducted by, for example, a method of
dipping the tube-like formed product in water controlled to room
temperature (25.degree. C.) or lower.
[0074] Since the multi-layer heat-shrinkable tube has the
fluorine-containing polymer layer crosslinked and expanded as the
outer layer, it is shrunk to the original diameter when it is
heated. When an adherend is covered with the multi-layer
heat-shrinkable tube according to the present invention, and the
tube is heat-shrunk, a coated product with the tube brought into
close contact with the surface of the adherend can be provided. The
heating conditions are within a range of preferably 100 to
250.degree. C., more preferably 130 to 200.degree. C., particularly
preferably 140 to 180.degree. C. The adhesive composition layer of
the inner layer melt-flows under the heating conditions and adheres
to the adherend. According to the multi-layer heat-shrinkable tube
of the present invention, a space between the tube and the adherend
can thus be completely filled. In addition, it has excellent
adhesive property to the adherent, so that penetration of air,
chemicals, water, moisture, etc. can be prevented.
[0075] Since the radiation-crosslinking composition forming the
outer layer and containing the fluorine-containing polymer is
irradiated and crosslinked, it is neither melted nor decomposed
under ordinary heating conditions upon heat shrinkage. In order to
prevent the outer layer from melting at the heating temperature
upon the heat shrinkage, it is desirable to use a
fluorine-containing polymer having a melting point of preferably at
least 110.degree. C., more preferably 110 to 200.degree. C.,
particularly preferably 140 to 200.degree. C.
[0076] On the other hand, the adhesive composition of the inner
layer is graft-modified by irradiation with the ionizing radiation,
but is not crosslinked, so that it has melt flowability. In order
for the adhesive composition arranged as the inner layer to exhibit
melt flowability under the heating conditions that the outer layer
develops the heat shrinkability, it is preferable to use, as the
fluorine-containing polymer making up the adhesive composition, a
fluororesin whose melting point is preferably not lower than
80.degree. C., but lower than 140.degree. C., more preferably 90 to
130.degree. C., or fluororubber whose Mooney viscosity
(ML.sub.1+10, 121.degree. C.) is generally about 5 to 70,
preferably about 10 to 50 from the viewpoint of balance between
heat resistance and melt flowability. A blend of the fluororesin
with the fluororubber may also be used to control the heat
resistance and melt flowability of the adhesive composition
layer.
[0077] FIG. 1 schematically illustrates a layer structure of a
multi-layer heat-shrinkable tube according to the present
invention. The multi-layer heat-shrinkable tube according to the
present invention is composed of an outer layer 1 that forms a body
of the heat-shrinkable tube, and an adhesive composition layer 2
arranged on an internal surface thereof.
[0078] The heat-shrinkable cap has a structure that one opening end
of a multi-layer heat-shrinkable tube having the same layer
structure as described above is heat-shrunk to seal the end with
the molten adhesive composition.
[0079] FIGS. 2 and 3 schematically illustrate a production process
and a structure of the heat-shrinkable cap, respectively. The
heat-shrinkable cap according to the present invention is formed
from a multi-layer heat-shrinkable tube composed of an outer layer
21 that forms a body of the heat-shrinkable tube, and an adhesive
composition layer 22 arranged on an internal surface thereof and
having a desired length. A rod 23 is inserted from one opening of
this heat-shrinkable tube up to the middle thereof, or the rod is
covered with the heat-shrinkable tube. The rod is preferably that
formed of a non-adhesive material, such as a
polytetrafluoroethylene rod.
[0080] When the heat-shrinkable tube is heated in the state shown
in FIG. 2, the tube is heat-shrunk at an opening end, in which no
rod is present, and the adhesive composition that is a material of
the inner layer is melted to seal the opening end. Thereafter, when
the rod is pulled out, a portion 26 that the heat-shrinkable tube
21 has been heat-shrunk at one opening end portion, and the
adhesive composition has been melted and filled therein is produced
as illustrated in FIG. 3. This heat-shrinkable cap 27 has a portion
24 linked to the other opening end and a sealed portion 25
heat-shrunk and filled with the adhesive composition.
[0081] FIG. 4 illustrates an exemplary use embodiment of this
heat-shrinkable cap. At an end of a covered cable 28 containing 3
electric wires 29, exposed conductors 30 are crimped and fixed by a
crimp sleeve 31 made of a metal, and covered with the
heat-shrinkable cap 27. Since the heat-shrinkable cap 27 is sealed
at one end, it is only necessary to insert the end portion of the
covered cable 28 from the other opening end. When the
heat-shrinkable cap is then heated to heat-shrink it, the cap is
brought into close contact with the end portion of the covered
cable.
EXAMPLES
[0082] The present invention will hereinafter be described more
specifically by the following Examples, Comparative Examples and
Referential Examples. Measuring methods of physical properties and
characteristics or properties, which are adopted in the present
invention, are as described in Example 1.
Example 1
1. Preparation of sample for evaluation of adhesive
composition:
[0083] In a twin-screw mixer preset at 180.degree. C., were melted
and kneaded 100 parts by weight of a ternary polyvinylidene
fluoride copolymer [product of Mitsubishi Chemical Corporation,
trade name "KYNAR 9300"; melting point=100.degree. C., melt flow
rate (MFR)=120 g/min (measured at a temperature of 190.degree. C.
under a load of 2.16 kg)], 3 parts by weight of glycidyl
methacrylate as an epoxy group-containing unsaturated compound and
0.5 parts by weight of
pentaerythritol-tetrakis[3-(3,5-di-t-butyl-4-hydroxy-phenyl)propionate]
as an antioxidant. The thus-obtained kneaded product was pelletized
by means of a pelletizer. The pellets were formed into a sheet
having a thickness of 1 mm by means of a hot press. This
hot-pressed sheet was irradiated with 60 kGy of electron rays of
acceleration voltage of 2 MeV to prepare a sample for
evaluation.
2. Test for initial adhesion strength to metal plates:
[0084] Strips of 20 mm in width and 100 mm in length were punched
out of the sample for evaluation. The strip and each of various
metal plates (a stainless steel plate, a copper plate, an iron
plate and an aluminum plate) of the same shape were heated and
pressurized under pressurization conditions of 160.degree. C. in
temperature, 2 MPs in pressure and 2 minutes in pressurizing time
by means of a hot press to laminate them. With respect to the
thus-obtained laminated samples, the peeling strength was measured
(n=3) by a T-shape peeling test (rate of pulling: 50 mm/min) to
regard an average value thereof as initial adhesion strength to its
corresponding metal plate, thereby evaluating the sample. In the
case of a heat-shrinkable tube used in a joint of a wire harness,
or the like and having a structure that a hot-melt adhesive layer
has been arranged as an inner layer, it has been found that
adhesion strength of at least 1.0 kg/cm is required in order to
remain the waterproofness of the joint. In the above-described
evaluation also, the fact that adhesion strength between the
adhesive and the metal is at least 1.0 kg/cm is used as a standard
of judgment for passing.
3. Evaluation of heat resistance:
[0085] The above-described laminated samples were subjected to
accelerated deterioration under conditions of 3,000 hours in a gear
oven of 150.degree. C. With respect to the samples after the
accelerated deterioration, the peeling strength (adhesive strength)
was measured in the same manner as described above.
[0086] The evaluation of the heat resistance is made in
consideration of the long-term heat resistance in the ISO Standard,
and the sample can be ranked as having a continuous service
temperature of at least 150.degree. C. where the adhesive strength
of the sample is at least 1.0 kg/cm after the accelerated
deterioration at 150.degree. C. for 3,000 hours.
4. Production of multi-layer heat-shrinkable tube:
[0087] A radiation-crosslinking composition obtained by blending 1
part by weight of trimethylolpropane trimethacrylate with 100 parts
by weight of a binary polyvinylidene fluoride copolymer [product of
Mitsubishi Chemical Corporation, trade name "KYNAR 2800"; melting
point=148.degree. C., MFR=0.2 g/10 min (measured at a temperature
of 230.degree. C. under a load of 2.16 kg)] was poured into a
melt-extruder for outer layer (40 mm in diameter; Hastelloy-worked
full-flight type), and the pellets of the composition prepared in
the item 1 and containing the ternary copolymer, glycidyl
methacrylate and the antioxidant were poured into a melt-extruder
for inner layer (30 mm in diameter; Hastelloy-worked full-flight
type) to melt-extrude them from a cross head for two-layer
extrusion at an extrusion temperature of 180.degree. C., thereby
forming a tube of a 2-layer structure having an inner diameter of
2.5 mm, an outer diameter of 6.5 mm and an inner layer thickness of
1 mm. This tube was irradiated with 60 kGy of electron rays of
acceleration voltage of 2 MeV to crosslink the outer layer and
graft-modify the inner layer.
[0088] The crosslinked tube was left to stand for 3 minutes in a
thermostatic chamber preset to 170.degree. C. to preheat it, and
then expanded by a method of blowing compressed air into an
interior cavity of the tube until the inner diameter reached 7.0
mm. Thereafter, the tube was immediately taken out of the
thermostatic chamber and cooled and solidified with water to fix
the form. The multi-layer heat-shrinkable tube obtained in such a
manner was cut into lengths of 60 mm.
5. Evaluation of waterproofness:
[0089] Seven fluororesin-coated cables (ARX-3KAI) manufactured by
Sumitomo Electric Industries, Ltd. and each having an outer
diameter of 1.25 mm (conductor=12/0.18, thickness=0.25 mm) were
joined to 4 fluororesin-coated cables (ARX-3KAI) manufactured by
Sumitomo Electric Industries, Ltd. and each having an outer
diameter of 1.48 mm (conductor=11/0.16, thickness=0.43 mm), and the
joint was covered with the multi-layer heat-shrinkable tube having
the length of 60 mm. The multi-layer heat-shrinkable tube was
shrunk at 520.degree. C. for 20 seconds by means of a batch type
shrink-processing machine manufactured by Sumitomo Electric
Industries, Ltd. to obtain a joint sample.
[0090] The multi-layer heat-shrinkable tube covered on the joint
was put into water to the depth of 30 mm (a twisted cable composed
of 7 copper wires on the water, and a twisted cable composed of 4
iron wires in the water), and pressurized air of 49 kPa was sent
for 30 seconds from an upper part of the tube to check whether air
leakage occurred or not. When no air leakage occurred, such a tube
was judged to have high waterproof performance and ranked as
"acceptance". When air leakage occurred, such a tube was judged to
be insufficient in waterproofness and ranked as "rejection"
(evaluation of initial waterproofness).
[0091] After the joint was deteriorated under conditions of
150.degree. C. in temperature (hot-air atmosphere) and 3,000 hours,
the waterproofness was evaluated in the same manner as described
above (evaluation of waterproofness after deterioration).
6. Result of evaluation:
[0092] As the result of the evaluation, it was found that the
adhesive composition described above has initial adhesion strength
of at least 1.0 kg/cm, and even in the evaluation of the initial
waterproofness using the multi-layer heat-shrinkable tube having
the adhesive composition as the inner layer, acceptance is gained
in all cases. It was also found that the adhesive composition
exhibits excellent heat resistance as demonstrated by the fact that
the adhesion strength after the deterioration at 150.degree. C. for
3,000 hours is at least 1.0 kg/cm, and acceptance is gained even-in
the evaluation of waterproofness after the deterioration. The
results are shown in Table 1.
Examples 2 to 12
[0093] Samples for evaluation of adhesive composition and
multi-layer heat-shrinkable tubes were produced in the same manner
as in Example 1 except that the kind of the fluorine-containing
polymer used in the adhesive composition, the kind and blending
proportion of the polar group-containing unsaturated compound, and
the quantity of the accelerated electron rays irradiated were
changed so as to be shown in Table 1, and evaluation was made in
the same manner as in Example 1. In each of the adhesive
compositions, 0.5 parts by weight of
pentaerythritol-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]
as an antioxidant were incorporated into 100 parts by weight of the
fluorine-containing polymer though not shown in Table 1.
[0094] As the result of the evaluation, it was found that the
adhesive compositions according to Examples 2 to 12 each have
initial adhesion strength of at least 1.0 kg/cm, and even in the
evaluation of the initial waterproofness using the multi-layer
heat-shrinkable tube having the adhesive composition as the inner
layer, acceptance is gained in all cases. It was also found that
the multi-layer heat-shrinkable tube exhibits excellent heat
resistance as demonstrated by the fact that the adhesion strength
after the deterioration at 150.degree. C. for 3,000 hours is at
least 1.0 kg/cm, and acceptance is gained even in the evaluation of
waterproofness after the deterioration. The results are shown in
Table 1. TABLE-US-00001 TABLE 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6
Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex. 12 PVdF-1 (*1) 100 -- -- -- 100
-- -- -- 100 -- -- -- PVdF-2 (*2) -- 100 -- -- -- 100 -- -- -- 100
-- -- FKM-1 (*3) -- -- 100 -- -- -- 100 -- -- -- 100 -- FKM-2 (*4)
-- -- -- 100 -- -- -- 100 -- -- -- 100 Glycidyl methacrylate 3 25
15 5 -- -- -- -- -- -- -- -- Diallylmonoglycidyl -- -- -- -- 3 10 5
25 -- -- -- -- isocyanate Maleic anhydride -- -- -- -- -- -- -- --
20 5 10 3 Quantity of kGy 60 20 200 400 650 300 250 20 100 500 300
600 electron rays Initial Stainless 1.7 1.9 1.8 1.9 1.6 2.1 2.0 1.8
1.9 1.7 1.8 1.8 adhesion Copper 1.7 1.7 1.8 1.7 1.5 1.7 1.9 1.8 1.6
1.7 1.6 1.7 strength, Iron 1.8 1.9 1.6 2 1.9 1.8 1.8 1.7 1.6 1.5
1.7 1.7 kg/cm Aluminum 1.9 1.9 1.8 1.6 1.6 1.8 1.8 1.6 1.8 1.6 1.7
1.8 Evaluation of initial Acpt. Acpt. Acpt. Acpt. Acpt. Acpt. Acpt.
Acpt. Acpt. Acpt. Acpt. Acpt. waterproofness by heat- shrinkable
tube Adhesion Stainless 1.2 1.6 1.4 1.5 1.1 1.8 1.6 1.4 1.4 1.3 1.5
1.2 strength Copper 1.2 1.3 1.4 1.5 1.1 1.4 1.3 1.4 1.3 1.2 1.3 1.3
after 150.degree. C. .times. 3000 hrs, Iron 1.4 1.6 1.4 1.6 1.4 1.6
1.4 1.4 1.3 1.2 1.4 1.2 kg/cm Aluminum 1.3 1.5 1.4 1.3 1.0 1.5 1.4
1.2 1.5 1.3 1.4 1.3 Evaluation of Acpt. Acpt. Acpt. Acpt. Acpt.
Acpt. Acpt. Acpt. Acpt. Acpt. Acpt. Acpt. waterproofness after
deterioration
(Note) [0095] (*1) PVdF-1: Ternary polyvinylidene fluoride
copolymer [product of Mitsubishi Chemical Corporation, trade name
"KYNAR 9300"; melting point=100.degree. C., MFR=120 g/min (measured
at a temperature of 190.degree. C. under a load of 2.16 kg)],
[0096] (*2) PVdF-2: Binary polyvinylidene fluoride copolymer
[product of Mitsubishi Chemical Corporation, trade name "KYNAR
7200"; melting point=120.degree. C., MFR=2 g/min (measured at a
temperature of 230.degree. C. under a load of 2.16 kg)], [0097]
(*3) FKM-1: Binary fluororubber [product of Du Pont, trade name
"Viton E-430"; fluorine content=66%, Mooney viscosity (ML.sub.1+10,
121.degree. C.)=20], [0098] (*4) FKM-2: Ternary fluororubber
[product of Du Pont, trade name "Viton B-50"; fluorine content=68%,
Mooney viscosity (ML.sub.1+10, 121.degree. C.)=30].
Examples 13 to 24
[0099] Samples for evaluation of adhesive composition and
multi-layer heat-shrinkable tubes were produced in the same manner
as in Example 1 except that a blend of a fluororesin and a
fluororubber was used as the fluorine-containing polymer used in
the adhesive composition as shown in Table 2, and the kind and
blending proportion of the polar group-containing unsaturated
compound, and the quantity of the accelerated electron rays
irradiated were changed so as to be shown in Table 2, and
evaluation was made in the same manner as in Example 1. In each of
the adhesive compositions, 0.5 parts by weight of
pentaerythritol-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]
as an antioxidant were incorporated into 100 parts by weight of the
fluorine-containing polymer though not shown in Table 2.
[0100] As the result of the evaluation, it was found that the
adhesive compositions according to Examples 13 to 24 each have
initial adhesion strength of at least 1.0 kg/cm, and even in the
evaluation of the initial waterproofness using the multi-layer
heat-shrinkable tube having the adhesive composition as the inner
layer, acceptance is gained in all cases. It was also found that
the multi-layer heat-shrinkable tubes exhibit excellent heat
resistance as demonstrated by the fact that the adhesion strength
after the deterioration at 150.degree. C. for 3,000 hours is at
least 1.0 kg/cm, and acceptance is gained even in the evaluation of
waterproofness after the deterioration. The results are shown in
Table 2. TABLE-US-00002 TABLE 2 Ex. 13 Ex. 14 Ex. 15 Ex. 16 Ex. 17
Ex. 18 Ex. 19 Ex. 20 Ex. 21 Ex. 22 Ex. 23 Ex. 24 pVdF-1 (*1) 50 80
-- -- 70 40 70 40 -- -- -- -- PVdF-2 (*2) -- -- 80 50 -- -- -- --
80 50 40 70 FKM-1 (*3) 50 -- 20 -- 30 -- 30 -- 20 -- 60 -- FKM-2
(*4) -- 20 -- 50 -- 60 -- 60 -- 50 -- 30 Glycidyl methacrylate 25
2.5 15 20 -- -- -- -- -- -- -- -- Diallylmonoglycidyl -- -- -- --
10 2 -- -- -- -- 15 10 isocyanate Maleic anhydride -- -- -- -- --
-- 15 3 25 5 -- -- Quantity of kGy 25 650 300 200 300 700 250 600
20 400 200 300 electron rays Initial Stainless 1.8 1.6 2.2 2.1 2.3
1.7 1.8 1.7 1.8 1.7 2.2 1.6 adhesion Copper 1.8 1.7 1.8 2.1 1.9 1.8
1.8 1.8 1.7 1.7 2.0 1.5 strength, Iron 1.6 1.6 2.0 2.3 2.1 1.6 1.6
1.6 1.8 1.8 2.0 1.5 kg/cm Aluminum 1.8 1.8 1.9 2.2 2.2 1.6 1.6 1.6
1.6 1.6 2.1 1.4 Evaluation of initial Acpt. Acpt. Acpt. Acpt. Acpt.
Acpt. Acpt. Acpt. Acpt. Acpt. Acpt. Acpt. waterproofness by
heat-shrinkable tube Adhesion Stainless 1.4 1.1 1.8 1.8 1.9 1.3 1.4
1.2 1.5 1.2 1.9 1.3 strength Copper 1.4 1.1 1.5 1.7 1.4 1.3 1.4 1.4
1.3 1.2 1.6 1.1 after 150.degree. C. .times. 3000 Iron 1.4 1.1 1.5
1.7 1.7 1.2 1.3 1.3 1.4 1.2 1.6 1.1 hrs, kg/cm Aluminum 1.4 1.4 1.4
1.9 1.6 1.2 1.3 1.3 1.3 1.1 1.7 1.0 Evaluation of Acpt. Acpt. Acpt.
Acpt. Acpt. Acpt. Acpt. Acpt. Acpt. Acpt. Acpt. Acpt.
waterproofness after deterioration
(Note) [0101] (*1) PVdF-1: Product of Mitsubishi Chemical
Corporation, trade name "KYNAR 9300" [melting point=100.degree. C.,
MFR=120 g/min (measured at a temperature of 190.degree. C. under a
load of 2.16 kg)], [0102] (*2) PVdF-2: Product of Mitsubishi
Chemical Corporation, trade name "KYNAR 7200" [melting
point=120.degree. C., MFR=2 g/min (measured at a temperature of
230.degree. C. under a load of 2.16 kg)], [0103] (*3) FKM-1:
Product of Du Pont, trade name "Viton E-430" [fluorine content=66%,
Mooney viscosity (ML.sub.1+10, 121.degree. C.)=20], [0104] (*4)
FKM-2: Product of Du Pont, trade name "Viton B-50" [fluorine
content=68%, Mooney viscosity (ML.sub.1+10, 121.degree.
C.)=30].
Comparative Examples 1 to 12
[0105] Samples for evaluation of adhesive composition and
multi-layer heat-shrinkable tubes were produced in the same manner
as in Example 1 except that the kind of the fluorine-containing
polymer used in the adhesive composition, and the kind and blending
proportion of the polar group-containing unsaturated compound were
changed so as to be shown in Table 3, and the accelerated electron
rays were not irradiated, and evaluation was made in the same
manner as in Example 1. In each of the adhesive compositions, 0.5
parts by weight of
pentaerythritol-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]
as an antioxidant were incorporated into 100 parts by weight of the
fluorine-containing polymer though not shown in Table 1.
[0106] As the result, the compositions according to Comparative
Examples 1 to 12 each had initial adhesion strength lower than 1.0
kg/cm, and the function as an adhesive was insufficient. Thus, the
evaluation of the adhesion strength after the deterioration at
150.degree. C. for 3,000 hours was not conducted.
[0107] It was found that in the evaluation of the initial
waterproofness using the multi-layer heat-shrinkable tube having,
as the inner layer, each of the compositions according to
Comparative Examples 1 to 12, rejection is given in all cases. It
was found that all these multi-layer heat-shrinkable tubes are also
rejected in the evaluation of waterproofness after the
deterioration at 150.degree. C. for 3,000 hours. The results are
shown in Table 3. TABLE-US-00003 TABLE 3 Comp. Comp. Comp. Comp.
Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. Ex. 1 Ex. 2 Ex. 3
Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex. 12 PVdF-1
(*1) 100 -- -- -- 100 -- -- -- 100 -- -- -- PVdF-2 (*2) -- 100 --
-- -- 100 -- -- -- 100 -- -- FKM-1 (*3) -- -- 100 -- -- -- 100 --
-- -- 100 -- FKM-2 (*4) -- -- -- 100 -- -- -- 100 -- -- -- 100
Glycidyl methacrylate 2 30 15 5 -- -- -- -- -- -- -- --
Diallylmonoglycidyl -- -- -- -- 3 10 5 25 -- -- -- -- isocyanate
Maleic anhydride -- -- -- -- -- -- -- -- 20 5 10 2.5 Quantity of
kGy 0 0 0 0 0 0 0 0 0 0 0 0 electron rays Initial Stainless 0.2 0.3
0.2 0.1 0.0 0.2 0.1 0.2 0.2 0.0 0.1 0.0 adhesion Copper 0.2 0.1 0.1
0.1 0.0 0.1 0.2 0.1 0.0 0.1 0.1 0.0 strength, Iron 0.1 0.1 0.1 0.1
0.1 0.2 0.1 0.2 0.2 0.0 0.1 0.0 kg/cm Aluminum 0.2 0.1 0.1 0.0 0.0
0.1 0.0 0.2 0.2 0.0 0.1 0.0 Evaluation of initial Reject Reject
Reject Reject Reject Reject Reject Reject Reject Reject Reject
Reject waterproofness by heat-shrinkable tube Adhesion Stainless --
-- -- -- -- -- -- -- -- -- -- -- strength Copper -- -- -- -- -- --
-- -- -- -- -- -- after 150.degree. C. .times. 3000 Iron -- -- --
-- -- -- -- -- -- -- -- -- hrs, kg/cm Aluminum -- -- -- -- -- -- --
-- -- -- -- -- Evaluation of Reject Reject Reject Reject Reject
Reject Reject Reject Reject Reject Reject Reject waterproofness
after deterioration
(Note) [0108] (*1) PVdF-1: Product of Mitsubishi Chemical
Corporation, trade name "KYNAR 9300" [melting point=100.degree. C.,
MFR=120 g/min (measured at a temperature of 190.degree. C. under a
load of 2.16 kg)], [0109] (*2) PVdF-2: Product of Mitsubishi
Chemical Corporation, trade name "KYNAR 7200" [melting
point=120.degree. C., MFR=2 g/min (measured at a temperature of
230.degree. C. under a load of 2.16 kg)], [0110] (*3) FKM-1:
Product of Du Pont, trade name "Viton E-430" [fluorine content=66%,
Mooney viscosity (ML.sub.1+10, 121.degree. C.)=20], [0111] (*4)
FKM-2: Product of Du Pont, trade name "Viton B-50" [fluorine
content=68%, Mooney viscosity (ML.sub.1+10, 121.degree.
C.)=30].
Comparative Examples 13 to 16 and Referential Example 1
[0112] Samples for evaluation of adhesive composition and
multi-layer heat-shrinkable tubes were produced in the same manner
as in Example 1 except that the kind of the fluorine-containing
polymer used in the adhesive composition, and the quantity of the
accelerated electron rays irradiated were changed so as to be shown
in Table 4, and the polar group-containing unsaturated compound was
not used, and evaluation was made in the same manner as in Example
1. In each of the adhesive compositions according to Comparative
Examples 13 to 16, 0.5 parts by weight of
pentaerythritol-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)prop-
ionate] as an antioxidant were incorporated into 100 parts by
weight of the fluorine-containing polymer though not shown in Table
4.
[0113] For the sake of reference, a sample for evaluation of
adhesive composition and a multi-layer heat-shrinkable tube were
produced in the same manner as in Example 1 except that a hot-melt
adhesive comprising a dimer acid type polyamide resin as a
principal component was used in place of the adhesive composition
making use of the fluorine-containing polymer, and the quantity of
the electron rays irradiated was changed to 200 kGy, and evaluation
was made in the same manner as in Example 1.
[0114] As the result, the compositions according to Comparative
Examples 13 to 16 each had initial-adhesion strength lower than 1.0
kg/cm, and the function as an adhesive was insufficient. With
respect to these compositions, thus, the evaluation of the adhesion
strength after the deterioration at 150.degree. C. for 3,000 hours
was not conducted.
[0115] It was found that in the evaluation of the initial
waterproofness using the multi-layer heat-shrinkable tube having,
as the inner layer, each of the compositions according to
Comparative Examples 13 to 16, rejection is given in all cases. It
was found that all these multi-layer heat-shrinkable tubes are also
rejected in the evaluation of waterproofness after the
deterioration at 150.degree. C. for 3,000 hours.
[0116] On the other hand, Referential Example 1 relates to a
hot-melt adhesive comprising a dimer acid type polyamide resin as a
principal component, and it was found that its initial adhesion
strength to the metals is as excellent as at least 1.0 kg/cm, and
even in the evaluation of the initial waterproofness using the
multi-layer heat-shrinkable tube having the hot-melt adhesive as
the inner layer, acceptance is gained. However, when the adhesive
was aged at 150.degree. C. for 3,000 hours in a gear oven, the
hot-melt adhesive was markedly deteriorated, so that it scarcely
exhibited adhesive property, and the adhesion strength thereof was
evaluated as 0 kg/cm. It was also found that this heat-shrinkable
tube is given rejection in the evaluation of waterproofness after
the deterioration TABLE-US-00004 TABLE 4 Comp. Comp. Comp. Comp.
Ex. 13 Ex. 14 Ex. 15 Ex. 16 Referential Ex. 1 PVdF-1 (*1) 100 -- --
-- Hot-melt adhesive comprising dimer acid type polyamide resin as
main component PVdF-2 (*2) -- 100 -- -- -- FKM-1 (*3) -- -- 100 --
-- FKM-2 (*4) -- -- -- 100 -- Glycidyl methacrylate -- -- -- -- --
Diallylmonoglycidyl -- -- -- -- -- isocyanate Maleic anhydride --
-- -- -- -- Quantity of kGy 700 200 400 20 200 electron rays
Initial Stainless 0.0 0.0 0.0 0.0 1.4 adhesion Copper 0.0 0.0 0.0
0.0 2.3 Strength, Iron 0.0 0.0 0.0 0.0 1.7 kg/cm Aluminum 0.0 0.0
0.0 0.0 1.5 Evaluation of initial Reject Reject Reject Reject
Acceptance waterproofness by heat-shrinkable tube Adhesion
Stainless -- -- -- -- 0.0 strength Copper -- -- -- -- 0.0 after
150.degree. C. .times. 3000 Iron -- -- -- -- 0.0 hrs, kg/cm
Aluminum -- -- -- -- 0.0 Evaluation of Reject Reject Reject Reject
Reject waterproofness after deterioration (Note) (*1) PVdF-1:
Product of Mitsubishi Chemical Corporation, trade name "KYNAR 9300"
[melting point = 100.degree. C., MFR = 120 g/min (measured at a
temperature of 190.degree. C. under a load of 2.16 kg)], (*2)
PVdF-2: Product of Mitsubishi Chemical Corporation, trade name
"KYNAR 7200" [melting point = 120.degree. C., MFR = 2 g/min
(measured at a temperature of 230.degree. C. under a load of 2.16
kg)], (*3) FKM-1: Product of Du Pont, trade name "Viton
E-430"[fluorine content = 66%, Mooney viscosity (ML.sub.1+10,
121.degree. C.) = 20], (*4) FKM-2: Product of Du Pont, trade name
"Viton B-50"[fluorine content = 68%, Mooney viscosity (ML.sub.1+10,
121.degree. C.) = 30].
Comparative Examples 17 to 32
[0117] Samples for evaluation of adhesive composition and
multi-layer heat-shrinkable tubes were produced in the same manner
as in Example 1 except that a blend of a fluororesin and a
fluororubber was used as the fluorine-containing polymer used in
the adhesive composition as shown in Table 5, and the kind and
blending proportion of the polar group-containing unsaturated
compound, and the quantity of the accelerated electron rays
irradiated were changed so as to be shown in Table 5, and
evaluation was made in the same manner as in Example 1. In each of
the adhesive compositions, 0.5 parts by weight of
pentaerythritol-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]
as an antioxidant were incorporated into 100 parts by weight of the
fluorine-containing polymer though not shown in Table 5.
[0118] As the result of the evaluation, it was found that when no
electron ray was irradiated (Comparative Examples 17 to 28) even
when the polar group-containing unsaturated compound was used, or
when no polar group-containing unsaturated compound was used
(Comparative Examples 29 to 32) even when the electron rays were
irradiated, all the adhesive compositions had initial adhesion
strength lower than 1.0 kg/cm, and could not sufficiently fulfill a
function as an adhesive. With respect to these compositions, thus,
the evaluation of the adhesion strength after the deterioration at
150.degree. C. for 3,000 hours was not conducted.
[0119] The test for the waterproofness using the multi-layer
heat-shrinkable tube having, as the inner layer, each of the
compositions according to Comparative Examples 17 to 32 revealed
that rejection is given in all cases of the evaluation as to the
initial waterproofness. It was found that all these multi-layer
heat-shrinkable tubes are also rejected in the evaluation of
waterproofness after the deterioration at 150.degree. C. for 3,000
hours. The results are shown in Table 5. TABLE-US-00005 TABLE 5
Comparative Example 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
PVdF-1 (*1) 50 80 -- -- 70 40 70 40 -- -- -- -- 50 80 -- -- PVdF-2
(*2) -- -- 80 50 -- -- -- -- 80 50 40 70 -- -- 80 50 FKM-1 (*3) 50
-- 20 -- 30 -- 30 -- 20 -- 60 -- 50 -- 20 -- FKM-2 (*4) -- 20 -- 50
-- 60 -- 60 -- 50 -- 30 -- 20 -- 50 Glycidyl methacrylate 30 2 10
25 -- -- -- -- -- -- -- -- -- -- -- -- Diallylmonoglycidyl -- -- --
-- 10 5 -- -- -- -- 15 3 -- -- -- -- isocyanate Maleic anhydride --
-- -- -- -- -- 15 5 10 2.5 -- -- -- -- -- -- Quantity of kGy 0 0 0
0 0 0 0 0 0 0 0 0 30 650 300 150 electron rays Initial Stainless
0.3 0.1 0.2 0.2 0.1 0.1 0.2 0.1 0.2 0.1 0.2 0.1 0.0 0.0 0.0 0.0
adhesion Copper 0.2 0.1 0.1 0.1 0.0 0.1 0.2 0.0 0.0 0.1 0.1 0.1 0.0
0.0 0.0 0.0 strength, Iron 0.2 0.2 0.1 0.1 0.1 0.1 0.1 0.2 0.2 0.1
0.1 0.1 0.0 0.0 0.0 0.0 kg/cm Aluminum 0.2 0.1 0.1 0.2 0.1 0.0 0.1
0.2 0.1 0.1 0.1 0.1 0.0 0.0 0.0 0.0 Evaluation of initial Rejt Rejt
Rejt Rejt Rejt Rejt Rejt Rejt Rejt Rejt Rejt Rejt Rejt Rejt Rejt
Rejt waterproofness by heat-shrinkable tube Adhesion Stainless --
-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- strength Copper -- --
-- -- -- -- -- -- -- -- -- -- -- -- -- -- after 150.degree. C.
.times. 3000 Iron -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
hrs, kg/cm Aluminum -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
Evaluation of Rejt Rejt Rejt Rejt Rejt Rejt Rejt Rejt Rejt Rejt
Rejt Rejt Rejt Rejt Rejt Rejt waterproofness after deterioration
(Note) (*1) PVdF-1: Product of Mitsubishi Chemical Corporation,
trade name "KYNAR 9300" [melting point = 100.degree. C., MFR = 120
g/min (measured at a temperature of 190.degree. C. under a load of
2.16 kg)], (*2) PVdF-2: Product of Mitsubishi Chemical Corporation,
trade name "KYNAR 7200" [melting point = 120.degree. C., MFR = 2
g/min (measured at a temperature of 230.degree. C. under a load of
2.16 kg)], (*3) FKM-1: Product of Du Pont, trade name "Viton
E-430"[fluorine content = 66%, Mooney viscosity (ML.sub.1+10,
121.degree. C.) = 20], (*4) FKM-2: Product of Du Pont, trade name
"Viton B-50"[fluorine content = 68%, Mooney viscosity (ML.sub.1+10,
121.degree. C.) = 30].
Comparative Examples 33 to 44
[0120] Samples for evaluation of adhesive composition and
multi-layer heat-shrinkable tubes were produced in the same manner
as in Example 1 except that the kind of the fluorine-containing
polymer used in the adhesive composition, and the quantity of the
accelerated electron rays irradiated were changed so as to be shown
in Table 6, and the proportion of the polar group-containing
unsaturated compound blended was changed to lower than 2 parts by
weight (Comparative Examples 33 to 38), or higher than 30 parts by
weight (Comparative Examples 39 to 44), and evaluation was made in
the same manner as in Example 1. In each of the adhesive
compositions prepared above, 0.5 parts by weight of
pentaerythritol-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]
as an antioxidant were incorporated into 100 parts by weight of the
fluorine-containing polymer though not shown in Table 6.
[0121] As the result, the adhesive compositions according to
Comparative Examples 33 to 44 each had initial adhesion strength
lower than 1.0 kg/cm, and could not sufficiently fulfill a function
as an adhesive. With respect to these compositions, thus, the
evaluation of the adhesion strength after the deterioration at
150.degree. C. for 3,000 hours was not conducted.
[0122] The test for the waterproofness using the multi-layer
heat-shrinkable tube having, as the inner layer, each of the
compositions according to Comparative Examples 33 to 44 revealed
that rejection is given in all cases of the evaluation as to the
initial waterproofness. It was found that all these multi-layer
heat-shrinkable tubes are also rejected in the evaluation of
waterproofness after the deterioration at 150.degree. C. for 3,000
hours. The results are shown in Table 6. TABLE-US-00006 TABLE 6
Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp.
Comp. Ex. 33 Ex. 34 Ex. 35 Ex. 36 Ex. 37 Ex. 38 Ex. 39 Ex. 40 Ex.
41 Ex. 42 Ex. 43 Ex. 44 PVdF-1 (*1) 100 -- 100 -- 100 -- 100 -- 100
-- 100 -- FKM-1 (*2) -- 100 -- 100 -- 100 -- 100 -- 100 -- 100
Glycidyl methacrylate 1.5 1 -- -- -- -- 35 31 -- -- -- --
Diallylmonoglycidyl -- -- 1 1.5 -- -- -- -- 40 35 -- -- isocyanate
Maleic anhydride -- -- -- -- 1.5 0.5 -- -- -- -- 50 32 Quantity of
kGy 100 550 650 500 300 700 50 200 150 300 20 350 electron rays
Initial Stainless 0.7 0.4 0.3 0.7 0.8 0.3 0.7 0.8 0.5 0.9 0.4 0.7
adhesion Copper 0.6 0.5 0.3 0.6 0.7 0.4 0.6 0.8 0.6 0.7 0.5 0.6
strength, Iron 0.8 0.5 0.3 0.7 0.7 0.5 0.7 0.8 0.6 0.7 0.6 0.5
kg/cm Aluminum 0.6 0.4 0.4 0.5 0.6 0.5 0.8 0.7 0.5 0.6 0.6 0.7
Evaluation of initial Reject Reject Reject Reject Reject Reject
Reject Reject Reject Reject Reject Reject waterproofness by
heat-shrinkable tube Adhesion Stainless -- -- -- -- -- -- -- -- --
-- -- -- strength Copper -- -- -- -- -- -- -- -- -- -- -- -- after
150.degree. C. .times. 3000 Iron -- -- -- -- -- -- -- -- -- -- --
-- hrs, kg/cm Aluminum -- -- -- -- -- -- -- -- -- -- -- --
Evaluation of Reject Reject Reject Reject Reject Reject Reject
Reject Reject Reject Reject Reject waterproofness after
deterioration (Note) (*1) PVdF-1: Product of Mitsubishi Chemical
Corporation, trade name "KYNAR 9300" [melting point = 100.degree.
C., MFR = 120 g/min (measured at a temperature of 190.degree. C.
under a load of 2.16 kg)], (*2) FKM-1: Product of Du Pont, trade
name "Viton E-430"[fluorine content = 66%, Mooney viscosity
(ML.sub.1+10, 121.degree. C.) = 20].
Comparative Examples 45 to 56
[0123] Samples for evaluation of adhesive composition and
multi-layer heat-shrinkable tubes were produced in the same manner
as in Example 1 except that the combination of the
fluorine-containing polymer blend used in the adhesive composition,
and the quantity of the accelerated electron rays irradiated were
changed so as to be shown in Table 7, and the proportion of the
polar group-containing unsaturated compound blended was changed to
lower than 2 parts by weight (Comparative Examples 45 to 50), or
higher than 30 parts by weight (Comparative Examples 51 to 56), and
evaluation was made in the same manner as in Example 1. In each of
the adhesive compositions prepared above, 0.5 parts by weight of
pentaerythritol-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]
as an antioxidant were incorporated into 100 parts by weight of the
fluorine-containing polymer though not shown in Table 7.
[0124] As the result, the adhesive compositions according to
Comparative Examples 45 to 56 each had initial adhesion strength
lower than 1.0 kg/cm, and could not sufficiently fulfill a function
as an adhesive. With respect to these compositions, thus, the
evaluation of the adhesion strength after the deterioration at
150.degree. C. for 3,000 hours was not conducted.
[0125] The test for the waterproofness using the multi-layer
heat-shrinkable tube having, as the inner layer, each of the
compositions according to Comparative Examples 45 to 56 revealed
that rejection is given in all cases of the evaluation as to the
initial waterproofness. It was found that all these multi-layer
heat-shrinkable tubes are also rejected in the evaluation of
waterproofness after the deterioration at 150.degree. C. for 3,000
hours. The results are shown in Table 7. TABLE-US-00007 TABLE 7
Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp.
Comp. Ex. 45 Ex. 46 Ex. 47 Ex. 48 Ex. 49 Ex. 50 Ex. 51 Ex. 52 Ex.
53 Ex. 54 Ex. 55 Ex. 56 PVdF-2(*1) 30 80 40 50 20 60 60 20 50 40 80
30 FKM-2(*2) 70 20 60 50 80 40 40 80 50 60 20 70 Glycidyl
methacrylate 1.5 1 -- -- -- -- 35 31 -- -- -- --
Diallylmonoglycidyl -- -- 1 1.5 -- -- -- -- 40 35 -- -- isocyanate
Maleic anhydride -- -- -- -- 1.7 0.5 -- -- -- -- 50 32 Quantity of
kGy 200 350 500 150 150 700 150 400 200 150 25 300 electron rays
Initial Stainless 0.8 0.6 0.5 0.7 0.8 0.4 0.6 0.7 0.6 0.8 0.6 0.7
adhesion Copper 0.8 0.6 0.4 0.8 0.6 0.2 0.6 0.6 0.6 0.8 0.5 0.7
strength, Iron 0.7 0.6 0.5 0.6 0.5 0.3 0.7 0.6 0.5 0.8 0.5 0.5
kg/cm Aluminum 0.7 0.7 0.3 0.8 0.6 0.4 0.6 0.7 0.5 0.7 0.4 0.4
Evaluation af initial Reject Reject Reject Reject Reject Reject
Reject Reject Reject Reject Reject Reject waterproofness by
heat-shrinkable tube Adhesion Stainless -- -- -- -- -- -- -- -- --
-- -- -- strength Copper -- -- -- -- -- -- -- -- -- -- -- -- after
150.degree. C. .times. 3000 Iron -- -- -- -- -- -- -- -- -- -- --
-- hrs, kg/cm Aluminum -- -- -- -- -- -- -- -- -- -- -- --
Evaluation of Reject Reject Reject Reject Reject Reject Reject
Reject Reject Reject Reject Reject waterproofness after
deterioration (Note) (*1)PVdF-2 Product of Mitsubishi Chemical
Corporation, trade name "KYNAR 7200" [melting point = 120.degree.
C., MFR = 2 g/min (measured at a temperature of 230.degree. C.
under a load of 2.16 kg)], (*2)FKM-2: Product of Du Pont, trade
name "Viton B-50"[fluorine content = 68%, Mooney viscosity
(ML.sub.1+10, 121.degree. C.) = 30].
Comparative Examples 57 to 68
[0126] Samples for evaluation of adhesive composition and
multi-layer heat-shrinkable tubes were produced in the same manner
as in Example 1 except that the kinds and combination of the
fluorine-containing polymers used in the adhesive composition, the
kind and proportion of the polar group-containing unsaturated
compound blended, and the quantity of the accelerated electron rays
irradiated were changed so as to be shown in Table 8, and
evaluation was made in the same manner as in Example 1. In each of
the adhesive compositions prepared above, 0.5 parts by weight of
pentaerythritol-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]
as an antioxidant were incorporated into 100 parts by weight of the
fluorine-containing polymer though not shown in Table 8.
[0127] As the result, the adhesive compositions according to
Comparative Examples 57 to 62, in which the quantity of the
electron rays irradiated was small, each had initial adhesion
strength lower than 1.0 kg/cm, and could not sufficiently fulfill a
function as an adhesive. With respect to these compositions, thus,
the evaluation of the adhesion strength after the deterioration at
150.degree. C. for 3,000 hours was not conducted.
[0128] The test for the waterproofness using the multi-layer
heat-shrinkable tube having, as the inner layer, each of the
compositions according to Comparative Examples 57 to 62 revealed
that rejection is given in all cases of the evaluation as to the
initial waterproofness. It was found that all these multi-layer
heat-shrinkable tubes are also rejected in the evaluation of
waterproofness after the deterioration at 150.degree. C. for 3,000
hours.
[0129] On the other hand, some of the adhesive compositions
according to Comparative Examples 63 to 68, in which the quantity
of the electron rays irradiated was great, had good initial
adhesion strength, and the multi-layer heat-shrinkable tubes
having, as the inner layer, these adhesive compositions also had
good initial waterproofness. However, these adhesive compositions
were markedly lowered in adhesion strength after the deterioration
at 150.degree. C. for 3,000 hours, and the waterproofness of the
heat-shrinkable tubes was also given rejection. The results are
shown in Table 8. TABLE-US-00008 TABLE 8 Comp. Comp. Comp. Comp.
Comp. Comp. Comp. Comp. Comp. Comp. Comp. Comp. Ex. 57 Ex. 58 Ex.
59 Ex. 60 Ex. 61 Ex. 62 Ex. 63 Ex. 64 Ex. 65 Ex. 66 Ex. 67 Ex. 68
PVdF-1(*1) 100 70 40 -- 30 80 100 -- 60 50 80 30 FKM-2(*2) -- 30 60
100 70 20 -- 100 40 50 20 70 Glycidyl methacrylate 20 15 -- -- --
-- 5 15 -- -- -- -- Diallylmonoglycidyl -- -- 3 30 -- -- -- -- 30
20 -- -- isocyanate Maleic anhydride -- -- -- -- 10 15 -- -- -- --
10 20 Quantity of kGy 15 10 18 17 10 5 900 850 730 750 800 730
electron rays Initial Stainless 0.6 0.5 0.9 0.8 0.6 0.7 0.9 1.0 1.5
1.4 1.1 1.7 adhesion Copper 0.3 0.4 0.8 0.9 0.7 0.7 0.6 0.8 1.4 1.6
1.0 1.6 strength, Iron 0.5 0.4 0.9 0.6 0.7 0.5 0.5 0.9 1.6 1.3 1.0
1.6 kg/cm Aluminum 0.5 0.4 0.6 0.8 0.4 0.8 0.7 0.8 1.5 1.5 1.2 1.3
Evaluation of initial Reject Reject Reject Reject Reject Reject
Reject Reject Acpt. Acpt. Acpt. Acpt. waterproofness by
heat-shrinkable tube Adhesion Stainless -- -- -- -- -- -- -- 0.2
0.6 0.4 0.3 0.6 strength Copper -- -- -- -- -- -- -- -- 0.3 0.3 0.2
0.4 after 150.degree. C. .times. 3000 Iron -- -- -- -- -- -- -- --
0.6 0.4 0.2 0.4 hrs, kg/cm Aluminum -- -- -- -- -- -- -- -- 0.6 0.5
0.3 0.4 Evaluation of Reject Reject Reject Reject Reject Reject
Reject Reject Reject Reject Reject Reject waterproofness after
deterioration (Note) (*1)PVdF-1 Product of Mitsubishi Chemical
Corporation, trade name "KYNAR 9300" [melting point = 100.degree.
C., MFR = 120 g/min (measured at a temperature of 190.degree. C.
under a load of 2.16 kg)], (*2)FKM-2: Product of Du Pont, trade
name "Viton B-50"[fluorine content = 68%, Mooney viscosity
(ML.sub.1+10, 121.degree. C.) = 30].
Example 25
[0130] A radiation-crosslinking composition obtained by blending 1
part by weight of trimethylolpropane trimethacrylate with 100 parts
by weight of a thermoplastic fluororesin [product of Sumitomo 3M
Limited, trade name "Dyneon THV220G"; melting point=110 to
130.degree. C., MFR=20 g/10 min (measured at a temperature of
250.degree. C. under a load of 5 kg)] was poured into a
melt-extruder for outer layer (40 mm in diameter; Hastelloy-worked
full-flight type). On the other hand, the pellets of the
composition prepared in Example 1 and containing the ternary
polyvinylidene fluoride copolymer, glycidyl methacrylate and the
antioxidant were poured into a melt-extruder for inner layer (30 mm
in diameter; Hastelloy-worked full-flight type). The respective
compositions were melt-extruded through a cross head for two-layer
extrusion at an extrusion temperature of 230.degree. C., thereby
forming a tube of a 2-layer structure having an inner diameter of
2.5 mm, an outer diameter of 6.5 mm and an inner layer thickness of
1.0 mm. This tube was irradiated with 60 kGy of electron rays of
acceleration voltage of 2 MeV to crosslink the outer layer and
graft-modify the inner layer.
[0131] The crosslinked tube was left to stand for 3 minutes in a
thermostatic chamber preset to 150.degree. C. to preheat it, and
then expanded by a method of blowing compressed air into an
interior cavity of the tube until the inner diameter reached 6.5
mm. Thereafter, the tube was immediately taken out of the
thermostatic chamber and cooled and solidified with water to fix
the form, thereby obtaining a multi-layer heat-shrinkable tube
(FIG. 1).
[0132] This heat-shrinkable tube was cut into lengths of 30 mm, and
as illustrated in FIG. 2, a columnar rod made of a
tetrafluoroethylene resin having an outer diameter of 6.0 mm was
covered with the tube so as to cover a 20-mm length of the rod. The
rod covered with the tube was dipped 3 minutes in a
high-temperature vessel of 150.degree. C. to shrink the tube to
produce a heat-shrinkable cap in a form that the internal layer
material (adhesive composition) of the heat-shrunk portion is
melted and sealed as illustrated in FIG. 3.
<Evaluation of Waterproofness>
[0133] The cover of a fluororesin-coated cable (ARX-3KAI)
manufactured by Sumitomo Electric Industries, Ltd. and having an
outer diameter of 1.48 mm (conductor=11/0.16, thickness=0.43 mm)
was removed to 5 mm at an end portion thereof, and conductors of 3
wires were crimped and fixed by means of a crimp sleeve (outer
diameter: 4.0 mm) made of a metal. As illustrated in FIG. 4, the
end portion of the fluororesin-coated cable was covered with the
heat-shrinkable cap produced above, and the heat-shrinkable cap was
left to stand for 3 minutes in a high-temperature vessel of
150.degree. C. to heat-shrink the cap, thereby obtaining a joint
sample.
[0134] After this joint sample was placed in a water vessel
containing a 5% aqueous solution of sodium chloride, and left to
stand for 1 hour at room temperature, a DC voltage of 500 V was
applied between the conductor of the cable and a counter electrode
provided in the water vessel to measure an insulation resistance.
As a result, it was confirmed that the insulation resistance was at
least 100 M.OMEGA., and sufficient air-tightness can be retained.
This joint sample was subjected to a deterioration test under
conditions of 150.degree. C. for 3,000 hours, and an insulation
resistance was measured in the same manner as described above. As a
result, it was found that the insulation resistance of at least 100
M.OMEGA. is retained, and so the joint sample is excellent in
waterproofness even after the deterioration.
Industrial Applicability
[0135] The adhesive compositions according to the present invention
can be hot-melted and are excellent in adhesive property to various
adherends including metallic adherends and heat resistance. The
adhesive compositions, and multi-layer heat-shrinkable tubes and
heat-shrinkable caps according to the present invention can be
suitably applied to protection of electric wires, wire harnesses
and pipes, of which high heat resistance that a continuous service
temperature is at least 150.degree. C. is required, and hermetic
sealing of joints and ends.
[0136] The adhesive compositions according to the present
invention, and formed products having a layer of the adhesive
composition, such as multi-layer heat-shrinkable tubes and
heat-shrinkable caps, are suitable for use in protection or
connection of parts used in automobiles, aircrafts, space
industries, or the like, of which high heat resistance is required,
and in imparting waterproofness thereto.
* * * * *