U.S. patent application number 14/009281 was filed with the patent office on 2014-02-06 for cover film.
This patent application is currently assigned to DENKI KAGAKU KOGYO KABUSHIKI KAISHA. The applicant listed for this patent is Tetsuo Fujimura, Takayuki Iwasaki, Takeshi Ono, Akira Sasaki, Kazuya Sugimoto, Yusuke Tanazawa, Hisatsugu Tokunaga, Tomoharu Watanabe. Invention is credited to Tetsuo Fujimura, Takayuki Iwasaki, Takeshi Ono, Akira Sasaki, Kazuya Sugimoto, Yusuke Tanazawa, Hisatsugu Tokunaga, Tomoharu Watanabe.
Application Number | 20140037940 14/009281 |
Document ID | / |
Family ID | 46969031 |
Filed Date | 2014-02-06 |
United States Patent
Application |
20140037940 |
Kind Code |
A1 |
Fujimura; Tetsuo ; et
al. |
February 6, 2014 |
COVER FILM
Abstract
A cover film including, at least, (A) a substrate layer, (B) an
intermediate layer, (C) a release layer and (D) a heat seal layer
is provided. The release layer (C) includes a resin composition
which includes (a) a styrene-based resin composition and (b) an
ethylene-.alpha.-olefin random copolymer, with the content of the
copolymer (b) in the release layer being 20 to 50 mass %, and which
has a Vicat softening temperature of 55 to 80.degree. C., while the
heat seal layer (D) includes an acrylic resin having a glass
transition temperature of 55 to 80.degree. C. By the cover film, a
carrier tape of polystyrene or the like can be so heat-sealed even
in a short time as to achieve sufficient peel strength. Further,
the resulting heat-sealed carrier tape exhibits little variation in
peel strength, so that when peeling, few components fly out of the
carrier tape.
Inventors: |
Fujimura; Tetsuo;
(Isesaki-shi, JP) ; Tokunaga; Hisatsugu;
(Isesaki-shi, JP) ; Tanazawa; Yusuke;
(Isesaki-shi, JP) ; Ono; Takeshi; (Isesaki-shi,
JP) ; Watanabe; Tomoharu; (Isesaki-shi, JP) ;
Sasaki; Akira; (Isesaki-shi, JP) ; Iwasaki;
Takayuki; (Isesaki-shi, JP) ; Sugimoto; Kazuya;
(Isesaki-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Fujimura; Tetsuo
Tokunaga; Hisatsugu
Tanazawa; Yusuke
Ono; Takeshi
Watanabe; Tomoharu
Sasaki; Akira
Iwasaki; Takayuki
Sugimoto; Kazuya |
Isesaki-shi
Isesaki-shi
Isesaki-shi
Isesaki-shi
Isesaki-shi
Isesaki-shi
Isesaki-shi
Isesaki-shi |
|
JP
JP
JP
JP
JP
JP
JP
JP |
|
|
Assignee: |
DENKI KAGAKU KOGYO KABUSHIKI
KAISHA
Tokyo
JP
|
Family ID: |
46969031 |
Appl. No.: |
14/009281 |
Filed: |
March 27, 2012 |
PCT Filed: |
March 27, 2012 |
PCT NO: |
PCT/JP2012/057942 |
371 Date: |
October 1, 2013 |
Current U.S.
Class: |
428/328 ;
428/336; 428/349 |
Current CPC
Class: |
B32B 27/32 20130101;
B32B 27/302 20130101; B32B 27/327 20130101; B32B 2250/04 20130101;
B32B 27/08 20130101; B32B 2439/00 20130101; B32B 2270/00 20130101;
Y10T 428/265 20150115; B32B 27/34 20130101; B32B 2274/00 20130101;
B32B 27/20 20130101; B32B 27/18 20130101; B65D 43/02 20130101; B32B
2307/20 20130101; B32B 27/308 20130101; B32B 27/36 20130101; Y10T
428/256 20150115; B32B 2307/202 20130101; Y10T 428/2826 20150115;
B32B 2307/308 20130101; B32B 2250/24 20130101 |
Class at
Publication: |
428/328 ;
428/349; 428/336 |
International
Class: |
B65D 43/02 20060101
B65D043/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 1, 2011 |
JP |
2011-081574 |
Claims
1. A cover film comprising at least, in order, a substrate layer
(A), an intermediate layer (B), a peel layer (C) and a heat seal
layer (D), wherein the peel layer (C) comprises a resin composition
comprising a styrenic resin composition (a) having a styrene-diene
block copolymer as a main component, and an ethylene-.alpha.-olefin
random copolymer (b), the ethylene-.alpha.-olefin random copolymer
occupying 20 to 50 mass % of the peel layer, and having a Vicat
softening temperature of 55 to 80.degree. C.; and the heat seal
layer (D) comprising an acrylic resin with a glass transition
temperature of 55 to 80.degree. C.
2. The cover film according to claim 1, wherein the thickness of
the substrate layer (A) after drying is 12 to 20 .mu.m, the
thickness of the intermediate layer (B) after drying is 10 to 40
.mu.m, the thickness of the peel layer (C) after drying is 5 to 20
.mu.m, and the total thickness of the cover film after drying is 45
to 65 .mu.m.
3. The cover film according to claim 1, wherein the heat seal layer
(D) comprises 100 to 700 parts by mass of conductive microparticles
of one of tin oxide, zinc oxide and zinc antimonate having a
mass-average particle size of 1.0 .mu.m or less, with respect to
100 parts by mass of the resin constituting the heat seal layer
(D).
4. The cover film according to claim 1, wherein the heat seal layer
(D) comprises 40 to 100 parts by mass of a cationic polymer-type
anti-static agent having a quaternary ammonium salt on a side
chain, with respect to 100 parts by mass of the resin constituting
the heat seal layer (D).
Description
TECHNICAL FIELD
[0001] The present invention relates to a cover film used in
packages for electronic components.
BACKGROUND ART
[0002] With the miniaturization of electronic devices, the
electronic components used therein have also become progressively
smaller and of higher performance, in addition to which the
components are automatically mounted on printed circuit boards
during assembly of the electronic devices. Surface-mounted
electronic components are housed in carrier tape with pockets that
are successively formed by thermoforming in accordance with the
shapes of the electronic components. After loading the electronic
components, a cover film is laid as a lid material over the top
surface of the carrier tape, and the ends of the cover film are
continuously heat-sealed in the longitudinal direction with a
heated seal bar to form packages. As cover film materials, those
having a heat seal layer of thermoplastic resin laminated onto a
biaxially stretched polyester film are used. Carrier tapes are
usually made of thermoplastic resins, such as polystyrenes,
polycarbonates or polyesters.
[0003] In recent years, electronic components such as capacitors,
resistors, transistors and LEDs have become increasingly smaller,
lighter and thinner, while production speeds have become faster,
making the requirements when heat-sealing a cover film to a carrier
tape stricter than in the past with regard to the performance on
the following two points. First, it must be capable of thermally
bonding to carrier tape materials such as polystyrenes,
polycarbonates and polyesters with sufficient peel strength even in
a very short sealing time. Second, variations in peel strength when
peeling the cover film should be small, in order to prevent
components from flying out of the carrier tape due to the
disparities in peel strength.
[0004] As a means to provide high-speed sealability to the cover
film, the use of a substrate layer of a suitable thickness for the
purpose of increasing the thermal conductivity of the cover film at
the time of heat sealing has been described (Patent Document 1).
Additionally, the idea of lowering the necessary heat for
heat-sealing by making the peel layer a suitable thickness has been
described (Patent Document 2). However, the high-speed sealing
described in these publications has a heat sealing time of 0.4 to
0.5 seconds, and adjustment of the thickness of the substrate layer
or peel layer is not an adequate solution for the ultra high-speed
heat sealing that is required for heat-sealing capacitors and
resistors of recent years. On the other hand, the idea of raising
the peel strength with respect to carrier tape even while reducing
the heat sealing time by including a fibrous substance on the
surface of the carrier tape bonding to the cover film has also been
described (Patent Document 3).
[0005] However, the cover film of Patent Document 3 is used for
carrier tapes composed of paper materials, and has insufficient
ultra high-speed sealability with respect to carrier tapes of
polystyrene, polycarbonate or polyester.
RELATED ART
Patent Documents
[0006] Patent Document 1: JP 2006-182418 A [0007] Patent Document
2: JP H11-278582 A [0008] Patent Document 3: JP 2009-46132 A
SUMMARY OF THE INVENTION
[0009] The present invention is directed to a cover film to be used
in combination with a carrier tape of polystyrene, polycarbonate,
polyester or the like, with the purpose of enabling thermal bonding
to such carrier tapes so as to have a sufficient peel strength even
with a very short heat sealing time, with little variation in peel
strength when peeling the cover film so as to prevent components
from flying out from the carrier tape when peeling the cover film
from the carrier tape.
[0010] As a result of diligent research into the aforementioned
problems, the present inventors found that a cover film that
overcomes the problems addressed by the present invention can be
obtained by a cover film comprising at least a substrate layer (A),
an intermediate layer (B), a peel layer (C) and a heat seal layer
(D), wherein the peel layer (C) is formed from a resin composition
having a specific Vicat softening temperature, and the heat seal
layer (D) is formed from a resin composition having a specific
glass transition temperature.
[0011] In other words, a first embodiment of the present invention
offers a cover film comprising at least, in order, a substrate
layer (A), an intermediate layer (B), a peel layer (C) and a heat
seal layer (D), wherein
[0012] the peel layer (C) comprises a resin composition comprising
a styrenic resin composition (a) having a styrene-diene block
copolymer as a main component, and an ethylene-.alpha.-olefin
random copolymer (b), the ethylene-.alpha.-olefin random copolymer
occupying 20 to 50 mass % of the peel layer, and having a Vicat
softening temperature of 55 to 80.degree. C.; and
[0013] the heat seal layer (D) comprising an acrylic resin with a
glass transition temperature of 55 to 80.degree. C.
[0014] In a further embodiment, the thickness of the substrate
layer (A) after drying is preferably 12 to 20 the thickness of the
intermediate layer (B) after drying is preferably 10 to 40 .mu.m,
the thickness of the peel layer (C) after drying is preferably 5 to
20 .mu.m, and the total thickness of the cover film after drying is
preferably 45 to 65
[0015] Furthermore, an embodiment of a heat seal layer (D) of the
present invention is characterized in that the heat seal layer (D)
comprises 100 to 700 parts by mass of conductive microparticles of
one of tin oxide, zinc oxide and zinc antimonate having a
mass-average particle size of 1.0 .mu.m or less, with respect to
100 parts by mass of the resin constituting the heat seal layer
(D). Another embodiment of the heat seal layer (D) is characterized
in that the heat seal layer (D) comprises 40 to 100 parts by mass
of a cationic polymer-type anti-static agent having a quaternary
ammonium salt on a side chain, with respect to 100 parts by mass of
the resin constituting the heat seal layer (D).
[0016] The present invention offers a cover film to be used in
combination with carrier tapes of polystyrene, polycarbonate and
polyester, which can be thermally bonded to such carrier tapes in a
manner such as to obtain sufficient peel strength even with a very
short sealing time, thereby increasing the number of electronic
components capable of being housed in the carrier tapes per unit
time and reducing variations in peel strength when peeling the
cover film so as to prevent components from flying out from the
carrier tape when peeling the cover film.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 A section view showing an example of a layer
arrangement of the cover film of the present invention.
[0018] FIG. 2 A section view showing an example of a layer
arrangement of the cover film of the present invention.
MODES FOR CARRYING OUT THE INVENTION
[0019] The cover film of the present invention comprises at least a
substrate layer (A), an intermediate layer (B), a peel layer (C)
and a heat seal layer (D). An example of an arrangement of the
cover film of the present invention is shown in FIG. 1. Substrate
layer (A) is a layer comprising a biaxially stretched polyester or
a biaxially stretched nylon, of which biaxially stretched
polyethylene terephthalate (PET) and polyethylene naphthalate
(PEN), biaxially stretched 6,6-nylon and 6-nylon, and biaxially
stretched polypropylene are particularly preferred. As the films
for the substrate layer, it is possible to use those that are
commonly used, as well as those to which an anti-static agent has
been applied or kneaded in as an anti-static treatment, or those
that have been subjected to a corona treatment or an easy-adhesion
treatment. If the substrate layer (A) is too thin, the tensile
strength of the cover film itself becomes low, making it
susceptible to "film rupture" when peeling the cover film. On the
other hand, if too thick, the heat-sealability of the carrier tape
may decrease. Additionally, if the substrate layer is thick, the
bending elasticity of the cover film itself becomes high, so that
when peeling the cover film, the force of separation from the
carrier tape acts at areas of low peel strength, causing the peel
strength to become even lower, and increasing the variations in
peel strength when peeling the cover film. Furthermore, in order to
avoid increased costs, those of thickness 12 to 20 .mu.m are
preferably used.
[0020] In the present invention, an intermediate layer (B) is
provided on one surface of the substrate layer (A) via an adhesive
layer if needed. The resin constituting the intermediate layer (B)
may be a low-density polyethylene (hereinafter referred to as
LDPE), a linear low-density polyethylene (hereinafter referred to
as LLDPE) or a linear low-density polyethylene polymerized with a
metallocene catalyst (hereinafter referred to as m-LLDPE), m-LLDPEs
being particularly preferred for their excellent tear strength. The
intermediate layer (B) has the effect of alleviating disparities in
head pressure when the sealing heads contact the cover film while
heat-sealing the cover film to the carrier tape, enabling the
substrate layer and the peel layer to be bonded evenly so as to
prevent variations in peel strength when peeling the cover film.
However, when m-LLDPEs are melt-extruded, it can sometimes be
difficult to obtain a film of even thickness, so a LDPE can be
added to the m-LLDPE to improve the film forming properties.
[0021] The above-mentioned m-LLDPE is a copolymer having, as
comonomers, an ethylene and an olefin having at least 3 carbon
atoms, preferably a linear, branched or aromatic
nucleus-substituted .alpha.-olefin having 3 to 18 carbon atoms.
Examples of linear mono-olefins include propylene, 1-butene,
1-pentene, 1-hexene, 1-octane, 1-nonene, 1-decene, 1-dodecene,
1-tetradecene, 1-hexadecene and 1-octadecene. Additionally,
examples of branched mono-olefins include 3-methyl-1-butene,
3-methyl-1-pentene, 4-methyl-1-pentene and 2-ethyl-1-hexene.
Additionally, styrenes and the like are examples of mono-olefins
substituted with an aromatic nucleus. These comonomers can be
copolymerized with ethylenes either singly or by combining two or
more types. Those using 1-hexene or 1-octene as comonomers have
good tensile strength and also excel in terms of cost, and are
therefore preferably used.
[0022] The thickness of the intermediate layer (B) is preferably 10
to 40 .mu.m. If the thickness of the intermediate layer (B) is less
than 10 .mu.m, there is a risk of the bonding strength between the
substrate layer (A) and the intermediate layer (B) becoming
insufficient, and the effect of reducing disparities in head
pressure of the sealing heads when heat-sealing cover films to
carrier tape is reduced, as a result of which variations in peel
strength when peeling the cover film are increased. On the other
hand, at more than 40 .mu.m, the heat of the sealing heads is less
easily transmitted to the heat seal boundary between the carrier
tape and the cover film when ultra high-speed heat-sealing a cover
film to a carrier tape, making it difficult to obtain sufficient
peel strength with the heat seal. Additionally, the bend elasticity
of the cover film itself becomes high, so during the peeling of the
cover film, bending of the cover film at areas of low peel strength
causes forces to act toward separation from the carrier tape,
further reducing the peel strength.
[0023] Therefore, if the intermediate layer is too thick,
variations are likely to occur in the peel strength when peeling
the cover film. Furthermore, thickening the intermediate layer
raises costs as well.
[0024] As described below, the intermediate layer (B) may be
composed of two or more layers depending on the method of
production of the cover film of the present invention.
[0025] The cover film of the present invention is provided with a
peel layer (C) between the intermediate layer (B) and the heat seal
layer (D). It is important that the thermoplastic resin used in
this peel layer comprise a styrenic resin composition (a) having a
styrene-diene block copolymer as a main component, and an
ethylene-.alpha.-olefin random copolymer (b) at a specific blending
proportion, and that component (b) occupy 20 to 50 mass % of the
peel layer (C). This peel layer (C) obtains a bonding force with
the heat seal layer (D) by means of component (a), enables the
bonding force to be adjusted to an appropriate value by containing
the aforementioned amount of component (b), and achieves sufficient
and stable peel strength between the peel layer (c) and the heat
seal layer (D) when peeling the heat-sealed cover film from the
carrier tape. If the amount of component (b) in the peel layer is
less than 20 mass %, the adhesive force between the peel layer (C)
and the heat seal layer (D) rises, increasing the variation in peel
strength and changing the peel strength with the passage of time
after heat sealing. On the other hand, if the amount of component
(b) exceeds 50 mass %, the bonding strength between the peel layer
(C) and the heat seal layer (D) becomes low, making it difficult to
obtain sufficient peel strength.
[0026] Furthermore, this peel layer (C) contains a resin
composition having a Vicat softening temperature of 55 to
80.degree. C., more preferably 60 to 75.degree. C., according to
JIS K-7206 method A120. Specifically, this Vicat softening
temperature was measured by setting a measurement sample flat
beneath the tip of a needle-shaped penetrator of an unweighted load
rod, five minutes later, placing weights on a weight dish so that
the total force on the sample is 10 N, then raising the temperature
of the heating device at a heating rate of 120.degree. C./hr, and
recording the temperature at which the tip of the penetrator
penetrates 1 mm into the sample from the position at the start of
the test. By using a resin composition with a Vicat softening
temperature of 55.degree. C. to 80.degree. C. for the peel layer
(C), the peel layer (C) softens during heat-sealing so that the
heat of the sealing heads is not easily transmitted to the boundary
between the carrier tape and the cover film, and the cover film can
be heat-sealed to the carrier tape in a very short sealing time.
When the Vicat softening temperature of the peel layer is less than
55.degree. C., the peel layer can soften and become fluid when
heat-sealing the cover film, as a result of which the peel layer
may be squeezed from the end portion of the cover film, soiling the
sealing heads and causing disparities in the peel strength, as well
as changing the peel strength due to the passage of time after
heat-sealing. On the other hand, when the Vicat softening
temperature of the peel layer (C) exceeds 80.degree. C., sufficient
peel strength cannot be obtained for ultra high-speed
heat-sealing.
[0027] The thickness of the peel layer (C) is normally 3 to 25
.mu.m, preferably 5 to 20 .mu.m. When the thickness of the peel
layer (C) is less than 3 .mu.m, sufficient peel strength may not be
obtained when heat-sealing the cover film to a carrier tape. On the
other hand, when the thickness of the peel layer (C) exceeds 25
.mu.m, sufficient peel strength cannot be obtained for ultra
high-speed heat-sealing, there tend to be disparities in peel
strength when peeling the cover film, and the costs tend to mount.
As explained below, the peel layer (C) can normally be formed by
thermally melting the resin composition to constitute the peel
layer in an extruder, and extruding from an inflation die or
T-die.
[0028] The cover film of the present invention has a heat seal
layer (D) on the surface of a peel layer (C). The thermoplastic
resin constituting the heat seal layer (D) is an acrylic resin
having a glass transition temperature of 55 to 80.degree. C., more
preferably 60 to 75.degree. C. Acrylic resins are materials that
are generally used to constitute carrier tapes, having superior
heat-sealing capability with respect to polystyrene, polycarbonate
and polyester resins. The acrylic resins constituting the heat seal
layer (D) are resins comprising at least 50 mass % of at least one
type of acryl residue including acrylic acid esters such as methyl
acrylate, ethyl acrylate, propyl acrylate and butyl acrylate,
methacrylic acid esters such as methyl methacrylate, ethyl
methacrylate, propyl methacrylate, butyl methacrylate and
cyclohexyl methacrylate, and may be resins obtained by
copolymerizing two or more types thereof. If the glass transition
temperature of the acrylic resin constituting the heat seal layer
(D) is less than 55.degree. C., the change in peel strength is
large when let stand for a long time after heat-sealing to a
carrier tape, so the peel strength lacks stability. On the other
hand, if the glass transition temperature of the acrylic resin
constituting the heat seal layer (D) exceeds 80.degree. C.,
sufficient peel strength cannot be obtained in the ultra high-speed
heat-seal. The glass transition temperature is the value obtained
when the heating speed is set to 10.degree. C. per minute in the
measurement method of JIS K7121. Specifically, the glass transition
temperature was measured using a thermal analyzer by setting about
1.5 mg of alumina as a reference substance and about 1.5 mg of a
measured sample in the holder portion, raising the temperature of
the nitrogen atmosphere from room temperature to 150.degree. C. at
a temperature ramp rate of 10.degree. C. per minute, and measuring
the difference in heat between the reference substance and the
measured sample. According to the present invention, a heat seal
layer comprising an acrylic resin with a specific glass transition
temperature is formed on the surface of a peel layer comprising a
thermoplastic resin with a Vicat softening temperature of 55 to
80.degree. C. comprising a styrene resin composition (a) and an
ethylene-.alpha.-olefin random copolymer (b), thereby softening the
peel layer (C) when heat-sealing so that the heat from the sealing
heads can be easily transmitted to the heat seal layer, and
enabling the heat seal layer to easily follow the contours of the
carrier tape surface, thereby resulting in better ultra high-speed
heat-sealing ability than various types of carrier tape materials
such as polystyrene, polycarbonate and polyester resins which are
materials constituting carrier tapes.
[0029] The thickness of the heat seal layer (D) is normally 0.1 to
2.0 .mu.m, preferably 0.3 to 1.0 .mu.m. When the thickness of the
heat seal layer (D) is less than 0.1 .mu.m, there may be
insufficient anti-static properties or peel strength when the cover
film is heat-sealed to carrier tape. On the other hand, if the
thickness of the heat seal layer (D) exceeds 2.0 Val, there is a
risk of variations occurring in the peel strength when peeling the
cover film, inviting cost increases. As mentioned below, the heat
seal layer (D) is usually formed by methods such as applying a
solution in which the resin composition constituting the heat seal
layer is dissolved in toluene or ethyl acetate, or applying an
emulsion of the resin constituting the heat seal layer, but in the
case of an application method, the thickness referred to here is
the thickness after drying.
[0030] The heat seal layer (D) may comprise at least one conductive
microparticle such as tin oxide, zinc oxide or zinc antimonate. Of
these, tin oxide doped with antimony, phosphorus or gallium raises
the conductivity with little loss of transparency, and is more
preferably used. The conductive microparticles of tin oxide, zinc
oxide or zinc antimonate may be spherical or acicular. The amount
added should normally be 100 to 1000 parts by mass, preferably 100
to 700 parts by mass with respect to 100 parts by mass of the
thermoplastic resin constituting the heat seal layer (D). When the
amount of conductive particles added is less than 100 parts by
mass, there is a risk that a heat seal layer (D) of the cover film
having a surface resistance of less than 10.sup.12.OMEGA. cannot be
obtained, and the cover film cannot be provided with sufficient
anti-static properties. On the other hand, if 700 parts by mass is
exceeded, the relative amount of thermoplastic resins is reduced,
making it difficult to obtain sufficient peel strength due to the
heat seal, and furthermore inviting reduced transparency of the
cover film or cost increases.
[0031] The heat seal layer (D) may comprise 40 to 100 parts by mass
of a cationic polymeric anti-static agent having a quaternary
ammonium salt side chain with monomer-derived repeating units
represented by the following general formula [Chem 1] with respect
to 100 parts by mass of the resin constituting the heat seal layer
(D). When less than 40 parts by mass of the polymeric anti-static
agent are added, there is a risk that the surface resistance of the
heat seal layer (D) of the cover film will be less than
10.sup.12.OMEGA., in which case sufficient anti-static properties
cannot be provided to the cover film. On the other hand, if more
than 100 parts by mass, the variation in peel strength when peeling
the cover film can become too large.
##STR00001##
[0032] In the formula, A denotes an oxygen atom or an imino group,
R.sub.1 denotes a hydrogen atom or a methyl group, R.sub.2 denotes
an alkylene group having 1 to 4 carbon atoms, R.sub.3, R.sub.4 and
R.sub.5 respectively denote alkyl groups having 1 to 18 carbon
atoms which may be the same or different, X.sup.- denotes an anion
such as a chloride ion, a bromide ion, a sulfate ion or a
methylsulfate ion, and n denotes an integer in the range of 100 to
5000.
[0033] The method of producing the cover film is not particularly
limited, and any common method may be used. For example, the peel
layer (C) may be pre-formed by a method such as T-die casting or
inflation. Furthermore, an anchor coating agent of polyurethane,
polyester, polyolefin or polyethyleneimine or the like may be
applied to the surface of a substrate layer (A) such as a biaxially
stretched polyester film, followed by sand lamination by extruding,
from a T-die, a resin composition mainly composed of a m-LLDPE to
form an intermediate layer (B) between the surface of application
of the anchor coating agent and the peel layer (C), resulting in a
three-layer film consisting of a substrate layer (A), an
intermediate layer (B) and a peel layer (C). Furthermore, the
desired cover film can be obtained by applying the resin
composition constituting the heat seal layer (D) onto the surface
of the peel layer (C), for example, with a gravure coater, a
reverse coater, a kiss coater, an air knife coater, a Meyer bar
coater or a dip coater.
[0034] As another method, a resin composition mainly composed of a
m-LLDPE constituting the intermediate layer (B) and a resin
composition constituting the peel layer (C) may be separately
extruded from a uniaxial extruder, then laminated by a
multimanifold die to form a two-layer film consisting of an
intermediate layer (B) and a peel layer (C). Then, an anchor
coating agent of polyurethane, polyester, polyolefin or the like is
coated onto the surface, for example, of a biaxially stretched
polyester film of the substrate layer (A), and the two-layer film
is laminated by dry lamination onto the surface of application of
the anchor coating agent, resulting in a three-layer film
consisting of a substrate layer (A), an intermediate layer (B) and
a peel layer (C). By further applying a resin composition
constituting the heat seal layer (D) onto the surface of the peel
layer (C) using, for example, a gravure coater, a reverse coater, a
kiss coater, an air knife coater, a Meyer bar coater or a dip
coater, a cover film can be obtained.
[0035] As yet another method, a resin composition mainly composed
of a m-LLDPE constituting a portion of intermediate layer (B) and a
resin composition constituting the peel layer (C) may be separately
extruded from a uniaxial extruder, then laminated with a
multimanifold die to form a two-layer film consisting of parts of
the intermediate layer (B) and a peel layer (C). Then, an anchor
coating agent of polyurethane, polyester, polyolefin,
polyethyleneimine or the like is coated onto the surface, for
example, of a biaxially stretched polyester film of the substrate
layer (A), and the resin composition mainly composed of a m-LLDPE
forming a portion of the intermediate layer (B) is extruded from a
T-die between the coating surface of the anchor coating agent and
the two-layer film by sand lamination, resulting in a three-layer
film consisting of a substrate layer (A), an intermediate layer (B)
and a peel layer (C). Furthermore, a resin composition constituting
the heat seal layer (D) may be applied to the surface of the peel
layer (C), for example, by a gravure coater, a reverse coater, a
kiss coater, an air knife coater, a Meyer bar coater or a dip
coater, to obtain a cover film. In this method, the intermediate
layer (B) has a two-layered structure consisting of a layer formed
by coextrusion with the peel layer (C) and a layer formed by sand
lamination. The thickness of the layer formed by sand lamination is
normally in the range of 10 to 20 .mu.m.
[0036] In addition to the above processes, the surface of the
substrate layer (A) of the cover film may be subjected to an
anti-static treatment as needed. Anti-static agents such as, for
example, anionic, cationic, non-ionic or betainic surfactant-type
anti-static agents or polymeric anti-static agents and conductive
agents such as polystyrene sulfonate and copolymers of acrylic acid
esters and quaternary ammonium acrylate may be applied by roll
coaters or lip coaters using gravure rollers, or by spraying.
Additionally, in order to apply these anti-static agents evenly,
the film surface should preferably be subjected to a corona
discharge treatment or ozone treatment, preferably a corona
discharge treatment, before performing the anti-static
treatment.
[0037] Cover films are used as lid members for carrier tapes which
are containers for housing electronic components. Carrier tapes are
in the form of ribbons about 8 mm to 100 mm wide, having recesses
for housing the electronic components. When heat-sealing a cover
film as a lid member, the material constituting the carrier tape is
not particularly limited, but the present invention can be suitably
used for polystyrene, polyester or polycarbonate carrier tapes. The
carrier tape may be made conductive by kneading carbon black or
carbon nanotubes into the resin, or provided with anti-static
properties by kneading in cationic, anionic or non-ionic
surfactant-type anti-static agents or permanent anti-static agents
such as polyether ester amides, or by applying to the surface a
coating solution having a surfactant-type anti-static agent or a
conductive material such as polypyrrole or polythiophene dispersed
in an organic binder.
[0038] A packaging for housing electronic components may, for
example, be obtained by placing electronic components or the like
in the recesses for housing electronic components in the carrier
tape, then packaging them by using sealing heads to continuously
heat-seal both end portions of the cover film in the longitudinal
direction using a cover film as the lid member, and winding the
result onto a reel. By packaging them in this form, the electronic
components or the like may be stored and transported. The package
of the present invention can be used to house and transport various
types of electronic components such as diodes, transistors,
capacitors, resistors and LEDs, and it particularly enables ultra
high-speed heat-sealing of electronic components with a thickness
of 1 mm or less such as LEDs, transistors, diodes and resistors,
thereby largely preventing the occurrence of trouble when mounting
electronic components. The package housing the electronic
components is conveyed using holes known as sprocket holes for
conveying the carrier tape provided on the edge portions in the
longitudinal direction of the carrier tape, while peeling the cover
film a little at a time, checking for the presence, orientation and
position of the electronic components and extracting them with a
component mounting device, then mounting them to a substrate.
[0039] If the peel strength is too small when peeling off the cover
film, the cover film may peel away from the carrier tape and the
housed components may fall out, while if too high, the carrier tape
may become difficult to peel and the cover film may be torn when
peeling. For this reason, the peel strength of the cover tape with
respect to the carrier tape, when subjected to ultra high-speed
heat-sealing at a sealing head temperature of 160 to 210.degree.
C., should be within the range of 0.20 to 0.70 N, preferably 0.35
to 0.60 N. For this reason, for ultra high-speed sealing at a
sealing head temperature of 210.degree. C., a cover tape with a
peel strength of at least 0.20 N and preferably at least 0.35 N may
be favorably used. Furthermore, in order to prevent electronic
components from flying out from the carrier tape when peeling the
cover film, the variation in peel strength should preferably be
0.30 N or less, more preferably 0.20 N or less. Additionally, after
housing the electronic components in the carrier tape and
heat-sealing the cover film, it may be exposed to a
high-temperature environment during transport or storage, so it is
important for the peel strength to remain stable even in a
high-temperature environment.
EXAMPLES
[0040] Herebelow, examples of the present invention will be
described in detail, but the present invention is not to be
construed as being limited thereby. In the examples and comparative
examples, the following raw materials were used for the substrate
layer (A), the intermediate layer (B), the peel layer (C) and the
heat seal layer (D).
(Material of Substrate Layer (A))
[0041] (a-1) Biaxially stretched polyethylene terephthalate film
(Toyo Boseki), 16 .mu.m thick (Resin of Intermediate Layer (B))
(b-1) m-LLDPE 1: Harmorex NH745N (Japan Polyethylene) (b-2) m-LLDPE
2: Evolue SP3010 (Prime Polymer) (b-3) LDPE 3: Ube Polyethylene
R500 (Ube Maruzen Polyethylene)
(Resin of Peel Layer (C))
[0042] (c-a-1) Styrene-butadiene block copolymer 1: Clearen 1
(Denka; Vicat softening temperature 76.degree. C., styrene
proportion 83 mass %) (c-a-2) Styrene-butadiene block copolymer 2:
TR-2000 (JSR; Vicat softening temperature 45.degree. C., styrene
proportion 40 mass %) (c-a-3) Styrene butadiene block copolymer 3:
Clearen 2 (Denka; Vicat softening temperature 93.degree. C.,
styrene proportion 82 mass %) (c-a-4) Styrene butadiene block
copolymer 4: Clearen 3 (Denka; Vicat softening temperature
63.degree. C., styrene proportion 70 mass %) (c-b-1)
Ethylene-.alpha.-olefin random copolymer 1: Kernel KF270T (Japan
Polyethylene; Vicat softening temperature 88.degree. C.) (c-b-2)
Ethylene-.alpha.-olefin random copolymer 2: Kernel KF360T (Japan
Polyethylene; Vicat softening temperature 72.degree. C.) (c-b-3)
Ethylene-.alpha.-olefin random copolymer 3: Tafiner A (Mitsui
Chemical; Vicat softening temperature 55.degree. C.) (c-b-4)
Ethylene-.alpha.-olefin random copolymer 4: Kernel KS240T (Japan
Polyethylene; Vicat softening temperature 44.degree. C.) (c-b-5)
Ethylene-.alpha.-olefin random copolymer 5: Kernel KF283 (Japan
Polyethylene; Vicat softening temperature 102.degree. C.) (c-c-1)
High-impact polystyrene: Toyo Styrol E640N (Toyo Styrene; Vicat
softening temperature 99.degree. C.)
(Resin of Heat Seal Layer (D))
[0043] (d-1) Acrylic resin 1: methyl methacrylate-butyl
acrylate-cyclohexyl methacrylate random copolymer emulsion solution
(Shin-Nakamura Chemical; glass transition temperature 60.degree.
C.) (d-2) Acrylic resin 2: methyl methacrylate-butyl methacrylate
random copolymer emulsion solution (Shin-Nakamura Chemical; glass
transition temperature 78.degree. C.) (d-3) Acrylic resin 3: methyl
methacrylate-butyl acrylate random copolymer emulsion solution
(Shin-Nakamura Chemical; glass transition temperature 55.degree.
C.) (d-4) Acrylic resin 4: styrene-butyl methacrylate random
copolymer emulsion solution (Shin-Nakamura Chemical; glass
transition temperature 70.degree. C.) (d-5) Acrylic resin 5: methyl
methacrylate-butyl methacrylate random copolymer emulsion solution
(Shin-Nakamura Chemical; glass transition temperature 85.degree.
C.) (d-6) Acrylic resin 6: methyl methacrylate-butyl acrylate
random copolymer emulsion solution (Shin-Nakamura Chemical; glass
transition temperature 45.degree. C.) (d-7) Conductive filler
solution: SN-100D (or SNS-10D; Ishihara Sangyo, antimony-doped tin
oxide, mass-average particle size 0.1 .mu.m) (d-8) Polymeric
anti-static agent solution: Bondeip PM (Altech; cationic polymer
anti-static agent comprising quaternary ammonium acrylate
salts)
Example 1
[0044] 52.5 parts by mass of (c-a-1) styrene-butadiene block
copolymer 1 "Clearen 1" (Denka), 12.5 parts by mass of (c-a-2)
styrene butadiene block copolymer 2 "TR-2000" (JSR) and 35 parts by
mass of (c-b-1) ethylene-.alpha.-olefin random copolymer 1 "Kernel
KF270T" (Japan Polyethylene) were pre-blended using a tumbler,
kneaded and extruded at 210.degree. C. using a 40 mm uniaxial
extruder to form a peel layer resin composition, then this peel
layer resin composition was formed into a film using an inflation
extruder to result in a 15 .mu.m-thick film constituting a peel
layer.
[0045] On the other hand, a two-agent cured polyurethane anchor
coating agent was applied using a roll coater to a biaxially
stretched polyethylene terephthalate film (16 thick) for
constituting the substrate layer, and between the coating surface
and the film constituting the above-described peel layer, a melted
(b-1) m-LLDPE 1 "Harmorex NH745N" (Japan Polyethylene) for
constituting the intermediate layer was extruded to a thickness of
25 .mu.m, to obtain a laminated film by extrusion lamination.
[0046] After subjecting the peel layer surface of this laminated
film to a corona treatment, a solution mixing the (d-1) acrylic
resin 1 "methyl methacrylate-butyl acrylate-cyclohexyl methacrylate
random copolymer emulsion solution" (Shin-Nakamura Chemical) and
(d-7) conductive filler solution "SN-100D" (Ishihara Sangyo) with a
resin and conductive filler mass ratio of 100:400 prepared
beforehand for the heat seal layer was applied to a post-drying
thickness of 0.5 .mu.m using a gravure coater, to obtain a cover
film having a substrate layer/intermediate layer/peel layer/heat
seal layer laminated structure. The properties of the cover film
are shown in Table 1.
Examples 2-14, Examples 17-23, Comparative Examples 1-9
[0047] Aside from using the resin compositions and thicknesses
shown in the below Tables 1 to 3, cover films were produced using
the same methods as Example 1.
Example 15
[0048] 52.5 parts by mass of (c-a-1) styrene-butadiene block
copolymer 1 "Clearen 1" (Denka), 12.5 parts by mass of (c-a-2)
styrene butadiene block copolymer 2 "TR-2000" (JSR) and 35 parts by
mass of (c-b-1) ethylene-.alpha.-olefin random copolymer 2 "Kernel
KF360T" (Japan Polyethylene) were pre-blended using a tumbler,
kneaded and extruded at 210.degree. C. using a 40 mm uniaxial
extruder to form a peel layer resin composition at a line speed of
20 m per minute. This peel layer resin composition and a mixture of
50 parts by mass of (b-2) m-LLDPE 2 "Evolue SP3010" (Prime Polymer)
and 50 parts by mass of (b-3) LDPE 3 "Ube Polyethylene R500" (Ube
Maruzen Polyethylene) for the first intermediate layer were
extruded from separate uniaxial extruders, then extruded in layers
from a multimanifold T-die to obtain a two-layer film having a peel
layer and first intermediate layer with thicknesses of respectively
7 .mu.m and 25 .mu.m.
[0049] On the other hand, a two-agent cured polyurethane anchor
coating agent was applied using a roll coater to a biaxially
stretched polyethylene terephthalate film (16 .mu.m thick) for
constituting the substrate layer, and between the coating surface
and the surface on the first intermediate layer side of the
above-described two-layer film, a melted (b-1) m-LLDPE 1 "Harmorex
NH745N" (Japan Polyethylene) for constituting the second
intermediate layer was extruded to a thickness of 13 .mu.m, to
obtain a laminated film by extrusion lamination.
[0050] After subjecting the peel layer surface of this laminated
film to a corona treatment, a solution mixing the (d-1) acrylic
resin 1 "methyl methacrylate-butyl acrylate-cyclohexyl methacrylate
random copolymer emulsion solution" (Shin-Nakamura Chemical) and
(d-7) conductive filler solution "SN-100D" (Ishihara Sangyo) with a
resin and conductive filler mass ratio of 100:400 prepared
beforehand for the heat seal layer was applied to a post-drying
thickness of 0.5 .mu.m using a gravure coater, to obtain a cover
film having a substrate layer/intermediate layer/peel layer/heat
seal layer laminated structure. The properties of the cover film
are shown in Table 2.
Example 16
[0051] Aside from using the resin compositions and thicknesses
shown in the below Table 2, cover films were produced using the
same methods as Example 15.
Comparative Example 10
[0052] 52.5 parts by mass of (c-a-1) styrene-butadiene block
copolymer 1 "Clearen 1" (Denka), 12.5 parts by mass of (c-a-2)
styrene butadiene block copolymer 2 "TR-2000" (JSR) and 35 parts by
mass of (c-b-1) ethylene-.alpha.-olefin random copolymer 1 "Kernel
KF270T" (Japan Polyethylene) were pre-blended using a tumbler,
kneaded and extruded at 210.degree. C. using a 40 mm uniaxial
extruder to form a peel layer resin composition, then this peel
layer resin composition was formed into a film using an inflation
extruder to result in a 15 .mu.m-thick film constituting a peel
layer.
[0053] On the other hand, a two-agent cured polyurethane anchor
coating agent was applied using a roll coater to a biaxially
stretched polyethylene terephthalate film (16 .mu.m thick) for
constituting the substrate layer, and between the coating surface
and the film constituting the above-described peel layer, a melted
(b-1) m-LLDPE 1 "Harmorex NH745N" (Japan Polyethylene) for
constituting the intermediate layer was extruded to a thickness of
25 .mu.m, to obtain a laminated film consisting of a substrate
layer/intermediate layer/peel layer by extrusion lamination. The
properties of this cover film are shown in Table 3.
<Evaluation Method>
(1) High-Speed Sealability of PS Carrier Tape
[0054] Using a heat sealer (Nitto Kogyo LTM-100), a 5.5 mm wide
cover film was heat-sealed to an 8 mm wide polystyrene conductive
carrier tape (Denka EC-R) using two sealing heads of width 0.5 mm,
sealing head length 30 mm, heat sealing temperature 210.degree. C.,
sealing pressure 3.5 kgf, feed length 4 mm, and sealing time 0.008
seconds.times.7.5 seals. The measurement of peel strength was made
after letting stand for 24 hours in an atmosphere of temperature
23.degree. C. and relative humidity 50%, and peeling 100 mm of the
cover film at a peel angle of 170.degree. to 180.degree. at a speed
of 300 mm per minute in the same atmosphere of temperature
23.degree. C. and relative humidity 50%. After heat sealing, the
cover film did not become peeled, and a peel strength of at least
0.3 N was necessary to stably house the components.
(2) Peel Strength Variation of Heat-Sealed Products with Respect to
Polystyrene Carrier Tape
[0055] Using a heat sealer (Nitto Kogyo LTM-100), a 5.5 mm wide
cover film was heat-sealed to an 8 mm wide polystyrene conductive
carrier tape (Denka EC-R) using two sealing heads of width 0.5 mm,
sealing head length 30 mm, heat sealing temperature 210.degree. C.,
sealing pressure 3.5 kgf, feed length 4 mm, and sealing time 0.008
seconds.times.7.5 seals, while adjusting the heat sealing
temperature so as to obtain an average peel strength of 0.40 N.
After letting stand for 24 hours in an atmosphere of temperature
23.degree. C. and relative humidity 50%, the peeling strength
variation (difference between the maximum value and the minimum
value) was measured when peeling 100 mm of the cover film at a peel
angle of 170.degree. to 180.degree. at a speed of 300 mm per minute
in the same atmosphere of temperature 23.degree. C. and relative
humidity 50%. Those having a peel strength of less than 0.40 N even
with a heat seal temperature of 235.degree. C. were left
unevaluated. When peeling the cover film, the peel strength
variation must be held to 0.3 N or less in order to prevent
components from flying out due to the disparities in peel
strength.
(3) Change Over Time of Peel Strength of Heat-Sealed Product with
Respect to Polystyrene Carrier Tape
[0056] Under the same conditions as in paragraph (1) above, the
heat seal temperature was adjusted to heat-seal a polystyrene
carrier tape (Denka EC-R) with an average peel strength of 0.40 N.
After letting the heat-sealed product stand for 7 days in a
60.degree. C. environment, the peel strength was measured under the
same conditions as the above paragraph (1). Those having a peel
strength of less than 0.40 N even with a heat seal temperature of
235.degree. C. were left unevaluated. Since the variation in peel
strength can be expected to increase if the peel strength becomes
too large after changes over time, the increase over the value of
paragraph (1) must be within 0.3 N.
(4) High-Speed Sealability of Polycarbonate Carrier Tape
[0057] Using a heat sealer (Nitto Kogyo LTM-100), a 5.5 mm wide
cover film was heat-sealed to an 8 mm wide polycarbonate conductive
carrier tape (3M No. 3000) using two sealing heads of width 0.5 mm,
sealing head length 30 mm, heat sealing temperature 210.degree. C.,
sealing pressure 3.5 kgf, feed length 4 mm, and sealing time 0.008
seconds.times.7.5 seals. The measurement of peel strength was made
after letting stand for 24 hours in an atmosphere of temperature
23.degree. C. and relative humidity 50%, and peeling 100 mm of the
cover film at a peel angle of 170.degree. to 180.degree. at a speed
of 300 mm per minute in the same atmosphere of temperature
23.degree. C. and relative humidity 50%. After heat sealing, the
cover film did not become peeled, and a peel strength of at least
0.3 N was necessary to stably house components.
(5) Surface Resistance
[0058] In accordance with the method of JIS K6911, Mitsubishi
Chemical Hiresta UPMCP-HT 450 was used to measure the surface
resistance of the surface of the heat seal layer of the cover film
at an applied voltage of 100 V in an atmosphere of temperature
23.degree. C. and relative humidity 50%, using a 70 mm surface
electrode with a positive electrode diameter of 50 mm and a
negative electrode diameter of 70 mm. A surface resistance of
10.sup.12.OMEGA. or less was required to provide the cover film
with a sufficient anti-static property.
TABLE-US-00001 TABLE 1 Type of Resin Ex 1 Ex 2 Ex 3 Ex 4 Ex 5 Ex 6
Substrate Substrate layer thiclmess (.mu.m) 16 16 16 16 16 16 Layer
Intermediate Intermediate layer thickness (.mu.m) 25 25 25 25 25 25
Layer Vicat softening Styrene temperature ratio (.degree. C.) (mass
%) Peel Layer St-Bd block copolymer resin 1 c-a-1 76 83 52.5 52.5
52.5 52.5 42.5 32.5 St-Bd block copolymer resin 2 c-a-2 45 40 12.5
12.5 12.5 12.5 12.5 12.5 St-Bd block copolymer resin 3 c-a-3 93 82
St-Bd block copolymer resin 4 c-a-4 63 70 Ethylene-.alpha.-olefin 1
c-b-1 88 -- 35 Ethylene-.alpha.-olefin 2 c-b-2 72 -- 35 35 35
Ethylene-.alpha.-olefin 3 c-b-3 54 -- 35 Ethylene-.alpha.-olefin 4
c-b-4 44 -- 35 Ethylene-.alpha.-olefin 5 c-b-5 102 -- High-impact
polystyrene c-c-1 99 95 10 20 Vicat softening temperature (.degree.
C.) of peel layer 76 71 64 61 73 75 Peel layer thickness (.mu.m) 15
15 15 15 15 15 Glass transition temperature (.degree. C.) Heat Seal
Acrylic resin 1 d-1 60 100 100 100 100 100 100 Layer Acrylic resin
2 d-2 78 Acrylic resin 3 d-3 55 Acrylic resin 4 d-4 70 Acrylic
resin 5 d-5 85 Acrylic resin 6 d-6 45 Conductive filler solution
d-7 -- 400 400 400 400 400 400 Polymeric anti-static agent d-8 --
solution Heat seal layer thickness (.mu.m) 0.5 0.5 0.5 0.5 0.5 0.5
Total thickness of cover film (.mu.m) 56.5 56.5 56.5 56.5 56.5 56.5
(1) High-speed sealability to polystyrene carrier tape units: N
0.54 0.56 0.54 0.51 0.45 0.41 (2) Peel strength variation for
polystyrene carrier tape units: N 0.08 0.11 0.14 0.16 0.09 0.11 (3)
Change over time in peel strength of polystyrene carrier tape
units: N 0.49 0.55 0.58 0.59 0.54 0.55 heat-sealed product (4)
High-speed sealability to polycarbonate carrier tape units: N 0.51
0.51 0.57 0.49 0.41 0.44 (5) Surface resistance units: .OMEGA.
10.sup.9 10.sup.9 10.sup.9 10.sup.9 10.sup.9 10.sup.9 Type of Resin
Ex 7 Ex 8 Ex 9 Ex 10 Ex 11 Ex 12 Substrate Substrate layer
thiclmess (.mu.m) 16 16 16 16 16 16 Layer Intermediate Intermediate
layer thickness (.mu.m) 25 25 25 25 25 25 Layer Vicat softening
Styrene temperature ratio (.degree. C.) (mass %) Peel Layer St-Bd
block copolymer resin 1 c-a-1 76 83 60 49 38 St-Bd block copolymer
resin 2 c-a-2 45 40 12.5 12.5 12.5 20 16 12 St-Bd block copolymer
resin 3 c-a-3 93 82 52.5 52.5 St-Bd block copolymer resin 4 c-a-4
63 70 52.5 Ethylene-.alpha.-olefin 1 c-b-1 88 -- 22 35 50
Ethylene-.alpha.-olefin 2 c-b-2 72 -- Ethylene-.alpha.-olefin 3
c-b-3 54 -- 35 35 Ethylene-.alpha.-olefin 4 c-b-4 44 -- 35
Ethylene-.alpha.-olefin 5 c-b-5 102 -- High-impact polystyrene
c-c-1 99 95 Vicat softening temperature (.degree. C.) of peel layer
73 70 58 74 75 78 Peel layer thickness (.mu.m) 15 15 15 15 15 15
Glass transition temperature (.degree. C.) Heat Seal Acrylic resin
1 d-1 60 100 100 100 100 100 100 Layer Acrylic resin 2 d-2 78
Acrylic resin 3 d-3 55 Acrylic resin 4 d-4 70 Acrylic resin 5 d-5
85 Acrylic resin 6 d-6 45 Conductive filler solution d-7 -- 400 400
400 400 400 400 Polymeric anti-static agent d-8 -- solution Heat
seal layer thickness (.mu.m) 0.5 0.5 0.5 0.5 0.5 0.5 Total
thickness of cover film (.mu.m) 56.5 56.5 56.5 56.5 56.5 56.5 (1)
High-speed sealability to polystyrene carrier tape units: N 0.47
0.49 0.67 0.55 0.48 0.37 (2) Peel strength variation for
polystyrene carrier tape units: N 0.09 0.13 0.23 0.28 0.17 0.12 (3)
Change over time in peel strength of polystyrene carrier tape
units: N 0.54 0.57 0.61 0.64 0.55 0.50 heat-sealed product (4)
High-speed sealability to polycarbonate carrier tape units: N 0.51
0.54 0.72 0.51 0.50 0.41 (5) Surface resistance units: .OMEGA.
10.sup.9 10.sup.9 10.sup.9 10.sup.9 10.sup.9 10.sup.9
TABLE-US-00002 TABLE 2 Type of Resin Ex 13 Ex 14 Ex 15 Ex 16 Ex 17
Ex 18 Substrate Substrate layer thickness (.mu.m) 16 16 16 16 16 16
Layer Intermediate Intermediate layer thickness (.mu.m) 25 25 38 45
25 25 Layer Vicat softening Styrene temperature ratio (.degree. C.)
(mass %) Peel Layer St-Bd block copolymer resin 1 c-a-1 76 83 40
52.5 52.5 52.5 52.5 St-Bd block copolymer resin 2 c-a-2 45 40 25 25
12.5 12.5 12.5 12.5 St-Bd block copolymer resin 3 c-a-3 93 82 40
St-Bd block copolymer resin 4 c-a-4 63 70 Ethylene-.alpha.-olefin 1
c-b-1 88 -- 35 35 Ethylene-.alpha.-olefin 2 c-b-2 72 -- 35 35 35 35
Ethylene-.alpha.-olefin 3 c-b-3 54 -- Ethylene-.alpha.-olefin 4
c-b-4 44 -- Ethylene-.alpha.-olefin 5 c-b-5 102 -- High-impact
polystyrene c-c-1 99 95 Vicat softening temperature (.degree. C.)
of peel layer 72 79 71 71 71 71 Peel layer thickness (.mu.m) 15 15
7 15 25 15 Glass transition temperature (.degree. C.) Heat Seal
Acrylic resin 1 d-1 60 100 100 100 100 100 Layer Acrylic resin 2
d-2 78 100 Acrylic resin 3 d-3 55 Acrylic resin 4 d-4 70 Acrylic
resin 5 d-5 85 Acrylic resin 6 d-6 45 Conductive filler solution
d-7 -- 400 400 400 400 400 400 Polymeric anti-static agent d-8 --
solution Heat seal layer thickness (.mu.m) 0.5 0.5 0.5 0.5 0.5 0.5
Total thickness of cover film (.mu.m) 56.5 56.5 61.5 76.5 66.5 56.5
(1) High-speed sealability to polystyrene carrier tape units: N
0.48 0.36 0.48 0.37 0.41 0.39 (2) Peel strength variation for
polystyrene carrier tape units: N 0.13 0.15 0.14 0.29 0.26 0.16 (3)
Change over time in peel strength of polystyrene carrier tape
units: N 0.59 0.55 0.64 0.65 0.64 0.60 heat-sealed product (4)
High-speed sealability to polycarbonate carrier tape units: N 0.49
0.38 0.50 0.41 0.43 0.40 (5) Surface resistance units: .OMEGA.
10.sup.9 10.sup.9 10.sup.9 10.sup.9 10.sup.9 10.sup.9 Type of Resin
Ex 19 Ex 20 Ex 21 Ex 22 Ex 23 Substrate Substrate layer thickness
(.mu.m) 16 16 16 16 16 Layer Intermediate Intermediate layer
thickness (.mu.m) 25 25 25 25 25 Layer Vicat softening Styrene
temperature ratio (.degree. C.) (mass %) Peel Layer St-Bd block
copolymer resin 1 c-a-1 76 83 52.5 52.5 52.5 52.5 52.5 St-Bd block
copolymer resin 2 c-a-2 45 40 12.5 12.5 12.5 12.5 12.5 St-Bd block
copolymer resin 3 c-a-3 93 82 St-Bd block copolymer resin 4 c-a-4
63 70 Ethylene-.alpha.-olefin 1 c-b-1 88 -- Ethylene-.alpha.-olefin
2 c-b-2 72 -- 35 35 35 35 35 Ethylene-.alpha.-olefin 3 c-b-3 54 --
Ethylene-.alpha.-olefin 4 c-b-4 44 -- Ethylene-.alpha.-olefin 5
c-b-5 102 -- High-impact polystyrene c-c-1 99 95 Vicat softening
temperature (.degree. C.) of peel layer 71 71 71 71 71 Peel layer
thickness (.mu.m) 15 15 15 15 15 Glass transition temperature
(.degree. C.) Heat Seal Acrylic resin 1 d-1 60 Layer Acrylic resin
2 d-2 78 100 100 100 Acrylic resin 3 d-3 55 100 Acrylic resin 4 d-4
70 100 Acrylic resin 5 d-5 85 Acrylic resin 6 d-6 45 Conductive
filler solution d-7 -- 400 400 Polymeric anti-static agent d-8 --
70 35 110 solution Heat seal layer thickness (.mu.m) 0.5 0.5 0.5
0.5 0.5 Total thickness of cover film (.mu.m) 56.5 56.5 56.5 56.5
56.5 (1) High-speed sealability to polystyrene carrier tape units:
N 0.65 0.52 0.41 0.44 0.37 (2) Peel strength variation for
polystyrene carrier tape units: N 0.12 0.14 0.23 0.14 0.30 (3)
Change over time in peel strength of polystyrene carrier tape
units: N 0.66 0.64 0.58 0.61 0.61 heat-sealed product (4)
High-speed sealability to polycarbonate carrier tape units: N 0.67
0.51 0.40 0.45 0.43 (5) Surface resistance units: .OMEGA. 10.sup.9
10.sup.9 10.sup.10 10.sup.13 10.sup.9
TABLE-US-00003 TABLE 3 Type of Resin Co Ex 1 Co Ex 2 Co Ex 3 Co Ex
4 Co Ex 5 Substrate Layer Substrate layer thickness (.mu.m) 16 16
16 16 16 Intermediate Layer Intermediate layer thickness (.mu.m) 25
25 25 25 25 Vicat softening Styrene temperature ratio (.degree. C.)
(mass %) Peel Layer St-Bd block copolymer resin 1 c-a-1 76 83 52.5
65 St-Bd block copolymer resin 2 c-a-2 45 40 12.5 12.5 12.5 12.5 20
St-Bd block copolymer resin 3 c-a-3 93 82 52.5 52.5 St-Bd block
copolymer resin 4 c-a-4 63 70 52.5 Ethylene-.alpha.-olefin 1 c-b-1
88 -- 35 15 Ethylene-.alpha.-olefin 2 c-b-2 72 --
Ethylene-.alpha.-olefin 3 c-b-3 54 -- Ethylene-.alpha.-olefin 4
c-b-4 44 -- 35 Ethylene-.alpha.-olefin 5 c-b-5 102 -- 35 35
High-impact polystyrene c-c-1 99 95 Vicat softening temperature
(.degree. C.) of peel layer 81 85 90 49 72 Peel layer thickness
(.mu.m) 15 15 15 15 15 Glass transition temperature (.degree. C.)
Heat Seal Layer Acrylic resin 1 d-1 60 100 100 100 100 100 Acrylic
resin 2 d-2 78 Acrylic resin 3 d-3 55 Acrylic resin 4 d-4 70
Acrylic resin 5 d-5 85 Acrylic resin 6 d-6 45 Conductive filler
solution d-7 -- 400 400 400 400 400 Polymeric anti-static agent d-8
-- solution Heat seal layer thickness (.mu.m) 0.5 0.5 0.5 0.5 0.5
Total thickness of cover film (.mu.m) 56.5 56.5 56.5 56.5 56.5 (1)
High-speed sealability to polystyrene carrier tape units: N 0.26
0.27 0.21 0.62 0.56 (2) Peel strength variation for polystyrene
carrier tape units: N 0.14 0.15 0.19 0.41 0.44 (3) Change over time
in peel strength of polystyrene carrier tape units: N 0.54 0.56
0.54 0.94 0.78 heat-sealed product (4) High-speed sealability to
polycarbonate carrier tape units: N 0.31 0.27 0.22 0.67 0.59 (5)
Surface resistance units: .OMEGA. 10.sup.9 10.sup.9 10.sup.9
10.sup.9 10.sup.9 Type of Resin Co Ex 6 Co Ex 7 Co Ex 8 Co Ex 9 Co
Ex 10 Substrate Layer Substrate layer thickness (.mu.m) 16 16 16 16
16 Intermediate Layer Intermediate layer thickness (.mu.m) 25 25 25
25 25 Vicat softening Styrene temperature ratio (.degree. C.) (mass
%) Peel Layer St-Bd block copolymer resin 1 c-a-1 76 83 36 52.5
52.5 52.5 St-Bd block copolymer resin 2 c-a-2 45 40 9 12.5 12.5
12.5 St-Bd block copolymer resin 3 c-a-3 93 82 St-Bd block
copolymer resin 4 c-a-4 63 70 Ethylene-.alpha.-olefin 1 c-b-1 88 --
55 Ethylene-.alpha.-olefin 2 c-b-2 72 -- 35 35 100 35
Ethylene-.alpha.-olefin 3 c-b-3 54 -- Ethylene-.alpha.-olefin 4
c-b-4 44 -- Ethylene-.alpha.-olefin 5 c-b-5 102 -- High-impact
polystyrene c-c-1 99 95 Vicat softening temperature (.degree. C.)
of peel layer 80 71 71 72 71 Peel layer thickness (.mu.m) 15 15 15
15 15 Glass transition temperature (.degree. C.) Heat Seal Layer
Acrylic resin 1 d-1 60 100 Acrylic resin 2 d-2 78 Acrylic resin 3
d-3 55 Acrylic resin 4 d-4 70 Acrylic resin 5 d-5 85 100 100
Acrylic resin 6 d-6 45 100 Conductive filler solution d-7 -- 400
400 400 400 Polymeric anti-static agent d-8 -- solution Heat seal
layer thickness (.mu.m) 0.5 0.5 0.5 0.5 -- Total thickness of cover
film (.mu.m) 56.5 56.5 56.5 56.5 56.0 (1) High-speed sealability to
polystyrene carrier tape units: N 0.17 0.31 0.67 0.04 0.45 (2) Peel
strength variation for polystyrene carrier tape units: N n/a 0.19
0.15 n/a 0.17 (3) Change over time in peel strength of polystyrene
carrier tape units: N n/a 0.55 0.87 n/a 0.54 heat-sealed product
(4) High-speed sealability to polycarbonate carrier tape units: N
0.20 0.29 0.69 0.03 0.10 (5) Surface resistance units: .OMEGA.
10.sup.9 10.sup.9 10.sup.9 10.sup.9 >10.sup.13
INDUSTRIAL APPLICABILITY
[0059] The cover film of the present invention can be used not only
for storage and transport of various types of electronic components
such as diodes, transistors, capacitors, resistors and LEDs wherein
high-speed sealing is performed, but with regard to packaging by
carrier tape for housing ICs and LSIs that are susceptible to the
influence of static electricity, with the potential for higher
utility as the trend toward ultra-high sealing progresses.
DESCRIPTION OF THE REFERENCE NUMBERS
[0060] 1 cover film [0061] 2 substrate layer [0062] 3 anchor
coating agent [0063] 4 intermediate layer [0064] 5 first
intermediate layer [0065] 6 second intermediate layer [0066] 7 peel
layer [0067] 8 heat seal layer
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