JP3492011B2 - Method for producing acrylic pressure-sensitive adhesive sheet - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to automobile parts and building materials.
Suitable for bonding fixed structures, and easy for bonding work
The present invention relates to a method for producing an acrylic pressure-sensitive adhesive sheet. [0002] Conventionally, the automobile industry, electric and electronic industry, building materials
As an alternative to structural adhesives in many fields, such as
Solvent-free work safety and sufficient pressure-sensitive adhesion
For example, due to high working efficiency,
Len foam, chloroprene foam, urethane foam
Body and acrylic foam, etc.
Double-sided adhesive tape with acrylic adhesive laminated on top
Used. [0003] However, in the above double-sided adhesive tape,
Foam used as a substrate has low interlayer strength
Foam cohesively breaks down, and is
Hard to obtain sufficient shear strength and peel strength
There was a problem. [0004] In order to solve the above problems, acrylic-based
Dispersed glass microbubbles in monomer mixture
Apply the photopolymerizable composition on the film with a thickness of several hundred μm.
Acrylic sheet obtained by photopolymerization
Disclosure of pressure-sensitive adhesive tape with another adhesive layer laminated on the substrate
(JP-B-57-17030). [0005] However, the above a
When manufacturing a cryl sheet material, the acrylic model
Microbubbles of glass with lower specific gravity compared to nomer mixtures
And disperse evenly to a thickness of several hundred μm.
A thixotropic agent is added to the above composition for coating.
It must be dissolved, which reduces cohesion and ultimately
Shear strength and peel strength of finally obtained pressure-sensitive adhesive tape
There is a problem that it is difficult to obtain a sufficient degree. In addition, the glass dispersed in the above composition
Light transmittance is hindered by
Of Acrylic Polymer Constituting Acrylic Sheet Substrate
Becomes uneven or the thermal conductivity decreases
As a result, the generated polymerization heat cannot be efficiently removed,
The degree of polymerization becomes non-uniform, and as a result
Is difficult to obtain in a stable manner.
Is not always efficient.
won. [0007] It is an object of the present invention to provide shear strength and peel strength.
To provide a method for producing an acrylic pressure-sensitive adhesive sheet having good
And there. [0008] A vinyl used in the present invention.
Alkyl-based monomer is an alkyl (meth) acrylate
(A) and a vinyl monomer (B) having a polar group
Become. The above alkyl (meth) acrylate (A)
Is an alkyl group having 4 to 18 carbon atoms, for example,
For example, n-butyl (meth) acrylate, sec-butyl
(Meth) acrylate, t-butyl (meth) acrylate
G, hexyl (meth) acrylate, 2-ethylhexyl
(Meth) acrylate, n-octyl (meth) acryl
Rate, isooctyl (meth) acrylate, n-noni
(Meth) acrylate, isononyl (meth) acryle
, Lauryl (meth) acrylate, stearyl (meth)
T) acrylates, etc., which are used alone
Or two or more of them may be used in combination. Ma
An alkyl group having 1 to 3 carbon atoms.
Although acrylate can be copolymerized, methyl (meth)
Acrylate, ethyl (meth) acrylate, propyl (meth)
T) Acrylates etc. increase the glass transition temperature
Therefore, it is preferable to keep the amount small. The above alkyl (meth) acrylate (A)
The lower the content, the higher the cohesion and the more pressure-sensitive
Adhesiveness is difficult to obtain, and the more it is, the lower the cohesive strength
And it is difficult to obtain sufficient shear strength.
Preferably 50 to 98% by weight in the nitro-based mixed monomer,
More preferably, it is 70 to 95% by weight. The above vinyl monomer having a polar group (B)
Is copolymerized with the above alkyl (meth) acrylate (A)
Possible, for example, (meth) acrylic acid,
Conic acid, crotonic acid, (anhydrous) maleic acid, (anhydrous)
Carboxy such as malic acid and carboxyethyl acrylate
Group-containing vinyl monomer, 2-hydroxyethyl (meth
(T) acrylate, 2-hydroxypropyl (meth) a
Acrylate, 4-hydroxybutyl (meth) acrylate
G, modified caprolactone (meth) acrylate, polyether
Tylene glycol (meth) acrylate, polypropylene
Hydroxyl-containing vinyl such as glycol (meth) acrylate
Monomer, (meth) acrylonitrile, N-vinyl
Loridone, N-vinylcaprolactam, N-vinyllau
Liloractam, (meth) acryloylmorpholine, (meth
TA) acrylamide, dimethyl (meth) acrylamide
, N-methylol (meth) acrylamide, N-but
Xymethyl (meth) acrylamide, dimethylaminop
Ropyl (meth) acrylamide, dimethylaminomethyl
(Meth) acrylate, dimethylaminoethyl (meth)
Acrylate, dimethylaminopropyl (meth) acryl
Rate, diethylaminoethyl (meth) acrylate, etc.
Nitrogen-containing vinyl monomers and the like.
Or may be used in combination of two or more.
No. The above vinyl monomer having a polar group (B)
The lower the content, the lower the cohesive strength and sufficient shear
It is difficult to obtain shear strength, and the more it is, the higher the cohesive strength
And it is difficult to obtain sufficient pressure-sensitive adhesiveness.
In the vinyl-based mixed monomer, preferably 2 to 50 weight
%, More preferably 5 to 30% by weight. The above alkyl (meth) acrylate (A)
And other than the vinyl monomer (B) having a polar group,
May be contained, for example, vinyl acetate
Nil, vinyl pivalate, vinyl propionate, styrene
And isobornyl (meth) acrylate.
These may be used alone or in combination of two or more.
May be used. [0014] The content of the other vinyl monomers is large.
The higher the cohesion, the more pressure-sensitive adhesiveness is obtained
In the vinyl-based mixed monomer,
Is not more than 30% by weight, more preferably not more than 20% by weight.
You. The thermopolymerizable composition used in the present invention is
Porous inorganic fine particles in the vinyl mixed monomer
(C), flat inorganic fine particles (D), non-polar organic fine particles
(E), any one of fine particles of crosslinked organic fine particles (F)
And a thermal decomposition type radical polymerization initiator. The above-mentioned fine particle filler is used in the production method of the present invention.
Improve the stress relaxation of the resulting acrylic pressure-sensitive adhesive sheet
To improve the shear strength and peel strength
Is added. The above-mentioned porous inorganic fine particles (C) are defined as a particle surface
Inorganic fine particles having a myriad of pores on the surface and a specific surface area of 3
0-1,000m ^Two / G, and medium
It may be empty or solid, specifically diatomaceous earth
Natural inorganic fine particles, hollow porous silica fine particles,
Synthetic inorganic fine particles such as crystalline silica fine particles and porous silica gel
And the like. Specific surface area of the porous inorganic fine particles (C)
Is smaller, the adhesive area at the interface of the fine particles is smaller,
It is difficult to obtain sufficient shear strength.
Particle strength is reduced, and sufficient shear strength and peel strength can be obtained.
30-1,000m ^Two / G is preferred
No. Average particle size of the porous inorganic fine particles (C)
Becomes too large to obtain sufficient shear strength
Therefore, it is limited to 100 μm or less, and 50 μm or less
preferable. The amount of the porous inorganic fine particles (C) added is
When the amount decreases, the shear strength of the acrylic adhesive sheet becomes sufficient
It becomes difficult to obtain, and when the amount increases, the above-mentioned thermopolymerizable composition
After polymerizing the polymer, the fluidity decreases and moldability is sufficiently obtained.
100% by weight of the above vinyl-based mixed monomer
Parts by weight, limited to 0.5 to 20 parts by weight, preferably
Is 1 to 15 parts by weight, more preferably 3 to 10 parts by weight.
You. The flat inorganic fine particles (D) are aspe
The flattened inorganic fine particles having an aspect ratio of 10 to 50,
For example, finely divided potassium / fluoric mica, finely divided sodium
Synthetic mica such as fluorine mica; and the degree of coloring.
Although the match is strong, mica such as musco bytes, phlogopite, etc.
Are also mentioned. As a commercial product, the product name "MK-10
0 "," MK-200 "," MK-300 "(all
High purity fluorine tetrasilicic mica such as
You. The average aspect ratio of the flat inorganic fine particles (D)
The impact ratio decreases as the shear strength of the acrylic adhesive sheet decreases.
It is difficult to obtain a sufficient degree,
It is difficult to obtain sufficient surface properties of the sheet,
~ 40 is preferred. Average diameter of the flat inorganic fine particles (D)
Becomes too large to obtain sufficient shear strength
Therefore, it is limited to 50 μm or less, and 30 μm or less is preferable.
No. The amount of the flat inorganic fine particles (D) added is
When the amount decreases, the shear strength of the acrylic adhesive sheet becomes sufficient
It becomes difficult to obtain, and when the amount increases, the above-mentioned thermopolymerizable composition
Of the acrylic pressure-sensitive adhesive sheet
Since it is difficult to obtain sufficient formability,
1 to 25 parts by weight, preferably 100 parts by weight of monomer
2 to 20 parts by weight, more preferably 3 to 15 parts by weight
It is. The non-polar organic fine particles (E) are remarkable.
Non-polar organic polymers, silicone polymers, etc.
Crosslinked fine particles, for example, low density polyethylene (L
DPE), linear low density polyethylene (LLDPE),
Polyethylene fine particles such as high-density polyethylene (HDPE)
Fiber, polypropylene fine particles, dimethyl silicone, etc.
And cone-based fine particles. Average particle size of the non-polar organic fine particles (E)
Is small, it is difficult to obtain shear strength and peel strength
Even if it increases, the same shear strength and peel strength can be obtained.
Is limited to 1 to 100 μm,
80 μm is preferable, and 5 to 50 μm is more preferable. The amount of the non-polar organic fine particles (E) added is
When the amount decreases, the shear strength of the acrylic adhesive sheet becomes sufficient
It becomes difficult to obtain, and when the amount increases, the above-mentioned thermopolymerizable composition
Of the acrylic pressure-sensitive adhesive sheet
Since it is difficult to obtain sufficient formability,
Limited to 5-80 parts by weight based on 100 parts by weight of monomer
And preferably 10 to 70 parts by weight, more preferably 1 to 70 parts by weight.
5 to 60 parts by weight. The above-mentioned crosslinked organic fine particles (F) are defined as a gel fraction
Are 30 to 98% by weight of organic fine particles.
Polymethyl methacrylate fine particles, cross-linked polystyrene fine particles
Particles or fine particles of crosslinked copolymer containing them as a main component
Particles, phenol resin fine particles, guanamine resin fine particles, etc.
No. The gel fraction of the crosslinked organic fine particles (F) is as follows:
When it is low, it softens at high temperatures and has sufficient shear strength and peel strength
Is difficult to obtain, and when it is high, the adhesiveness with the adhesive
Is not sufficiently obtained, and the peel strength is reduced.
8% by weight is preferred, 50-98% by weight is more preferred
No. Average particle size of the crosslinked organic fine particles (F)
Is small, it is difficult to obtain shear strength and peel strength
In addition, when it is large, moldability and peel strength are sufficiently obtained.
Because it is difficult, it is limited to 6 to 100 μm,
μm is preferred. The amount of the crosslinked organic fine particles (F) added is small.
When it runs out, the shear strength of the acrylic pressure-sensitive adhesive sheet
Becomes difficult to be obtained, and when the amount increases,
Flowability after polymerization decreases, forming acrylic pressure-sensitive adhesive sheet
Since it is difficult to obtain sufficient properties,
Limited to 5-70 parts by weight for 100 parts by weight of Nomer
And preferably 10 to 50 parts by weight, more preferably 15 to 50 parts by weight.
４０40 parts by weight. The thermal decomposition type radical polymerization initiator is generally
Used for radical polymerization of acrylic monomers
Is not particularly limited, for example, benzoyl peroxy
Side, 2,4-dichlorobenzoyl peroxide,
p-chlorobenzoyl peroxide, o-chloroben
Zoyl peroxide, bis-3,5,5-trimethyl
Diacyl peroxide such as cyclohexanol peroxide
Oxide, dicumyl peroxide, 2,5-dimethyl
-2,5-di- (t-butylperoxy) hexane, t
-Butylcumyl peroxide, di-t-butylperoxide
Oxide, 1,3-bis- (t-butylperoxyiso
Propyl) benzene and other dialkyl peroxides,
1,1-di- (t-butylperoxy) cyclohexane
Peroxyketal, t-butyl peroxybenzo, etc.
Alkyl ester such as Ethate, diisopropyl par
Organic peroxides such as percarbonates such as oxydicarbonate
Oxide, 2,2′-azobis-isobutyronitrile,
2,2'-azobis-2,4-dimethylvaleronitrile
2,2'-azobiscyclohexylnitrile, 1,2
1'-azobis (cyclohexane-1-carbonitrile
)), 2-phenylazo-4-methoxy-2,4-dimethyl
Examples include azo compounds such as tilvaleronitrile,
Good solubility in acrylic monomer used in the present invention
Benzoyl peroxide, 2,2 '
-Azobis-isobutyronitrile, 2,2'-azobis
-2,4-dimethylvaleronitrile, 1,1'-azobi
(Cyclohexane-1-carbonitrile), 2-Fe
Nylazo-4-methoxy-2,4-dimethylvaleronito
Ril is preferably used. Addition amount of the above-mentioned thermal decomposition type radical polymerization initiator
Decreases, the amount of radicals generated during polymerization becomes insufficient,
It is difficult to obtain a polymer with sufficient conversion within the set residence time.
The higher the number, the higher the amount of radicals generated and the higher the polymer
Molecular weight decreases and it is difficult to obtain sufficient shear strength
Therefore, based on 100 parts by weight of the vinyl-based mixed monomer,
And preferably 0.01 to 2 parts by weight, more preferably
0.02 to 1 part by weight. The essential components of the thermopolymerizable composition are as described above.
However, if necessary, the series should be maintained as long as the physical properties are not impaired.
Chain transfer agents, tackifiers, stabilizers, plasticizers, etc. are added
Also, the amount of these additives is the above-mentioned vinyl-based mixed monomer
Preferably not more than 10 parts by weight based on 100 parts by weight.
You. As the chain transfer agent, for example, n-butyl
Chill mercaptan, n-octyl mercaptan, n-do
Decyl mercaptan, t-dodecyl mercaptan, etc.
And the amount of addition is 100
0.01 to 0.1 part by weight based on part by weight is preferred. As the tackifier, for example, C5 series
And C9 (hydrogenated) petroleum resin, (hydrogenated) rosin resin,
(Hydrogenated) rosin ester resin, (hydrogenated) terpene resin,
(Hydrogenated) terpene phenolic resin, (hydrogenated) coumarone
Indene resin, disproportionated rosin resin, disproportionated rosin ester
Resin, polymerized rosin resin, polymerized rosin ester resin
All tackifiers, but added before polymerization.
Lowers the polymerization rate and lowers the molecular weight of the resulting polymer
Therefore, for example, the above chain transfer agent
It is necessary to appropriately adjust the amount of such addition. Further, since polymerization inhibition is relatively small,
For example, C5 and C9 hydrogenated petroleum resins, hydrogenated rosin
Resin, hydrogenated rosin ester resin, hydrogenated terpene resin, water
Terpene phenol resin, hydrogenated coumarone / indene tree
Fat, disproportionated rosin resin, disproportionated rosin ester resin, heavy
Unsaturated bonds such as compound rosin resin and polymerized rosin ester resin
Preference is given to tackifiers with low
They may be used, or two or more kinds may be used in combination. The above tackifier is contained in an acrylic pressure-sensitive adhesive sheet.
Will remain as an uncrosslinked component, and as the amount added increases,
The collecting force is low, and sufficient shear strength cannot be obtained. others
Therefore, the amount added is 100 parts by weight of the vinyl-based mixed monomer.
On the other hand, preferably 30 parts by weight or less, more preferably 2 parts by weight.
0 parts by weight or less. The acrylic pressure-sensitive adhesive sheet of the present invention
The obtained thermopolymerizable composition is supplied into a screw extruder.
Then, it is obtained by heat polymerization. The screw extruder used in the present invention
A single screw extruder, a twin screw extruder
And multi-screw extrusion with three or more screws
Machine is used. Example of single screw extruder
For example, in addition to those with full flight screws,
Continuous flight type screw, pin barrel, mixing head
And a twin-screw extruder
For example, meshing co-rotating type, meshing different
Directional rotation type, non-meshing different direction rotation type, and the like.
Screw shape is not particularly limited, but isotropic
1 to 3 type for directional rotation type, 1 to 8 for different direction rotation type
It is a needle type, partially
For rotating disks, seal rings, reverse screws, rotors, etc.
It may have a screw element. Also parallel
Any of a screw type and a conical screw type may be used.
In particular, meshing (self-wiping)
Direction rotation type twin screw extruder has high heat exchange performance,
Further, it is preferably used in that the long-term residence is small. The above-mentioned thermopolymerizable composition is subjected to the above-mentioned screw extrusion.
There is no particular limitation on the method of supplying the machine.
In addition, for example, the above-mentioned constituents of the thermopolymerizable composition
Vinyl-based mixed monomer, particulate filler, pyrolytic radio
The polymerization initiator and other additives using a stirring tank, etc.
May be supplied from one supply port
And also some of these pre-mixed,
Or even if you supply each one separately from a separate supply port
Good. The above-mentioned thermopolymerizable composition is continuously added to the above-mentioned screen.
Generally, a pump is used when feeding the extruder
All commercially available solution transfer pumps can be used.
For example, plunger pumps, chemical gear pumps
And a roller pump. The above-mentioned thermopolymerizable composition is subjected to the above-mentioned screw extrusion.
To prevent oxygen inhibition of the polymerization reaction
To produce a low molecular weight component with a weight average molecular weight of around 1,000
For the purpose of prevention, dissolved oxygen is removed by nitrogen replacement etc.
The dissolved oxygen concentration is preferably 1 ppm or less,
More preferably, it is 0.5 ppm or less. To obtain the acrylic pressure-sensitive adhesive sheet,
The polymerization temperature of the thermopolymerizable composition is set in the screw extruder.
It is necessary to adjust appropriately according to the set temperature of the barrel,
When the temperature is low, the polymerization takes time.
Increase the amount of oil generated and decrease the weight average molecular weight.
Does not rise, so there is not enough
Since it is difficult to obtain a retention time, preferably 60 to 20
It is 0 degreeC, More preferably, it is 80-160 degreeC. The inside of the screw extruder is supplied
Along the process where the monomer is polymerized
Section and the rear section, and the barrel temperature for each section is set separately.
It is possible to specify. Set temperature of each section is extruder
Average residence time, type of acrylic monomer, heat content
Should be determined appropriately depending on the type of depolymerization radical polymerization initiator
However, the suppression of boiling and vaporization of monomers in the front stage, the middle stage
Control at the stage, stable screw pumping pin at the later stage
Considering the control of the internal filling state that enables
It is desirable to be determined. Average residence time in the screw extruder
Is the supply rate of the thermopolymerizable composition, the reaction temperature,
It is determined by the viscosity until it becomes a polymer. Also on
The viscosity is the composition of the thermopolymerizable composition, the barrel setting temperature.
Degree, barrel diameter and barrel length of screw extruder, thread
Screw shape and rotation speed, screw extruder outlet
Minute breaker, die head, die mold, etc.
Adjustment is necessary. The average residence time in the above screw extruder
As a method for measuring the time, for example, the thermopolymerizable composition
At the same time, inject a small amount of an appropriate organic dye from the
Of the dye concentration in the polymer obtained in the above by spectrophotometry
To measure the residence time distribution and calculate the average residence time.
There is a method of obtaining. The acrylic adhesive used in the present invention
To obtain a suitable sheet with a narrow molecular weight distribution
Into, the heat-polymerizable composition obtained above, a screw extruder
By heating in a bulk and performing bulk polymerization, the desired monomer
A polymerization step of previously obtaining an acrylic polymer having a conversion rate or less,
Next, it was provided near the exit of the screw extruder.
Use a vent to remove residual monomer, or
An acrylic polymer having a predetermined monomer conversion rate or less,
Screw for demonomerization with separate vacuum vent function
Re-enter the extruder (hereinafter referred to as “de-monomer extruder”)
To remove residual monomers
Can be used, but demonomerization can be performed efficiently.
Therefore, it is preferable to use the latter demonomer extruder.
Good. The conversion of the vinyl-based mixed monomer is high.
When low, mainly low-molecular-weight polymers formed late in the polymerization
Resulting in a broader molecular weight distribution and, as a result,
Is difficult to obtain sufficient heat resistance of acrylic adhesive sheet
Therefore, preferably 90% by weight or less, more preferably
85% by weight or less, particularly preferably 80% by weight or less
You. The demonomer extruder is a vacuum venting machine.
This is a general screw extruder with
As the type, the screw press used in the polymerization process described above
Outboards are all listed, especially meshing (self-wiping
G) Different direction rotating twin screw extruder is preferably used.
It is. The above-mentioned vacuum venting function is defined as
-A vent is provided at the opening in the barrel of the extruder,
Is depressurized by a vacuum pump, and the polymer flowing there
The remaining monomer in the gas is vaporized and sucked into the system.
It is a function to take out. A vacuum vent device is usually provided with a vent port and a vacuum port.
Pump, drain trap, and the tube connecting them
System by installing a vacuum gauge near the vent port.
It is possible to know the degree of vacuum.
0 mmHg or less, more preferably 100 mmHg
It is as follows. The above demonomer extruder has at least one
Vent port is required, but it can improve the efficiency of demonomerization.
From the above, preferably two places, more preferably three or more places
And if there are multiple vents,
Connecting lines directly connected to the vacuum pump separately
This is preferable in that the monomer is effectively used. At least one of the plurality of vents is provided
What is on the upstream side of the mouth, the so-called rear vent
Is preferred in that demonomerization occurs early.
No. In the polymerization step, the tip of the screw extruder
The end outlet was directly connected to the supply port of the demonomer extruder,
By using the so-called tandem method, the polymerization process and
Continuous nomer process improves energy efficiency
You. The acrylic pressure-sensitive adhesive sheet of the present invention comprises
At the exit of the screw extruder or the demonomer extruder
Formed into a sheet or film by the provided die
It is obtained by doing. In addition, multiple layers with other substrates
Easy-to-handle shapes such as extrusions, rods and strands
And then press the other substrate by any method such as hot pressing.
It may be in the form of a sheet. Creep characteristics of the acrylic pressure-sensitive adhesive sheet
May be cross-linked for the purpose of improving
Irradiating the above acrylic pressure-sensitive adhesive sheet directly with an electron beam
Method, acrylic viscosity obtained from the above screw extruder
After adding and mixing the polyfunctional vinyl monomer to the
Acrylic adhesive in sheet form by molding into sheet form
There is a method of obtaining a sheet and further irradiating ultraviolet rays or electron beams
Or adding a polyfunctional vinyl monomer to the thermopolymerizable composition.
After making a sheet-like acrylic adhesive sheet,
A method of irradiating an outside line or an electron beam may be used. As the above polyfunctional vinyl monomer, for example,
For example, 1,4-butanediol di (meth) acrylate,
1,6-hexanediol di (meth) acrylate,
1,9-nonanediol di (meth) acrylate, (poly
G) ethylene glycol di (meth) acrylate,
Re) propylene glycol di (meth) acrylate, ne
Opentyl glycol di (meth) acrylate, penta
Erythritol di (meth) acrylate, glycerin
Tacrylate acrylate, pentaerythritol tri
(Meth) acrylate, trimethylolpropanetri
(Meth) acrylate, polyethylene glycol di (meth)
T) acrylate, N, N-dimethylmethylenebisac
Rilamide, allyl (meth) acrylate, (meth) acyl
Examples thereof include vinyl acrylate and divinylbenzene. That
Other epoxy (meth) acrylate, polyester
(Meth) acrylate, urethane (meth) acrylate
And the like. These may be used alone or 2
More than one kind may be used in combination. Glass transition temperature of the acrylic pressure-sensitive adhesive sheet
If the temperature is 50 ° C or less, use a dryer or the like at the time of bonding.
It becomes an adhesive sheet that expresses adhesive strength with some heating,
Adhesive sheet that exhibits adhesive strength at room temperature when the temperature is 20 ° C or less
When the temperature is below -10 ° C, the sticking property at low temperature is excellent.
Adhesive sheet. The production method of the present invention uses a screw extruder.
Since it is a bulk polymerization and no solvent is used,
No time or energy is required for placing or drying.
In addition, the obtained acrylic pressure-sensitive adhesive sheet contains various fine particles.
High elastic modulus due to dispersed filler, shear strength
It is considered that has improved. Further, during large deformation such as peeling,
Exfoliation at the interface between the limmer matrix and various particulate fillers
Causes numerous infinitesimal break points, dispersing the peeling energy
It is thought that the peel strength is improved
You. In the present invention, various kinds of fine particle fillers are
It is possible to achieve uniform dispersion by dispersing
In addition, the maximum performance is exhibited by the sufficient contact between the two interfaces
This is thought to be because after the polymer is polymerized,
The method of mixing the fine particle filler is not sufficiently achieved
This is supported by the fact. In addition, the screw extruder
This is a problem with conventional photopolymerization methods.
Settling and agglomeration of various particulate fillers after coating
There is no such problem. Examples of the present invention will be described below. still,
Hereinafter, “parts” means “parts by weight”. (Preparation of thermopolymerizable composition) [Examples 1 and 2, Comparative Examples 1 to 4] According to the composition shown in Table 1.
2-ethylhexyl as a monomer in a container equipped with a stirrer
Sil acrylate (hereinafter referred to as "2EHA"), n-butyl
Cyl acrylate (hereinafter referred to as "BA"), acrylic acid
(Hereinafter referred to as “AAc”), N-vinyl-2-pyrrolide
(Hereinafter referred to as “NVP”), 2,2′-azobis
(2,4-dimethylvaleronitrile), a particulate filler and
And hollow porous silica fine particles that are porous inorganic fine particles
(Average particle diameter 14 μm, specific surface area 715 m ^Two / G, Suzuki
Made by Yushi Kogyo Co., Ltd., trade name "Godball B-25C"
Below "B-25C"), porous amorphous silica fine particles
(Average particle diameter 0.7 μm, specific surface area 55 m ^Two / G, Mizusawa
Product name “Mizukasil P-527U” manufactured by Chemical Industry Co., Ltd.
Below "P-527U") or porous silica gel
(Average particle diameter 350 μm, specific surface area 650 m ^Two / G,
Product name “MS GEL D-35” manufactured by Dokai Chemical Industry Co., Ltd.
0-60A ”, hereinafter referred to as“ D-350 ”).
After stirring, the flow rate was 1.5 liter / m while maintaining the temperature at 25 ° C.
in nitrogen gas (purity 99.9%)
Basic meter (Central Chemical Co., Ltd., product name "UC-12"
-SOL type "), the dissolved acid in the above thermopolymerizable composition.
Thermal polymerization with nitrogen substitution until element concentration reaches 0.1 ppm
The composition was obtained. [Examples 3 to 5, Comparative Examples 5 to 6]
According to the composite composition, as the fine particle filler, flat inorganic fine particles
Synthetic mica (average particle diameter 3 μm, average aspect ratio
30, Corp Chemical Co., trade name "MK-100",
Hereinafter referred to as “MK-100”), (average particle diameter 7 μm,
Average aspect ratio 30, manufactured by Corp Chemical Co., trade name
"MK-200", hereinafter "MK-200"),
(Average particle diameter 15 μm, average aspect ratio 30, cope
Product name “MK-300” manufactured by Chemical Co., Ltd.
300 "), except that
A thermopolymerizable composition was obtained by the method. Examples 6 to 8, Comparative Examples 7 to 10
According to the composition, non-polar organic fine particles
Silicone fine particles (average particle diameter 10 μm,
Made by Les Dow Corning, Inc., trade name "Trefill E-50
1 ", hereinafter referred to as" E-501 "), silicone-based fine particles
(Average particle size 0.3 μm, manufactured by Toshiba Silicone Co., Ltd.
Name "Tospearl 103", hereinafter "T-103"
), Polypropylene fine particles (average particle diameter 35 μm,
Product name "Floprene B-200" manufactured by Yusei Chemical Co., Ltd.
"B-200"), low density polyethylene fine particles
(Average particle diameter 10 μm, manufactured by Sumitomo Seika Co., Ltd., trade name “Flow
Bead CL-2080 ", hereinafter referred to as" CL-2080 ".
Low-density polyethylene particles (average particle size 180μ)
m, manufactured by Sumitomo Seika Co., Ltd., trade name, trade name "Flow beads CL
−2507 ”, hereafter referred to as“ CL-2507 ”).
Except that the thermopolymerizable composition was prepared in the same manner as in Example 1.
Obtained. [Examples 9 to 10, Comparative Examples 11 to 14] Table
According to the composition of No. 4, as a fine particle filler, a crosslinked organic fine
Crosslinked polymethyl methacrylate fine particles (average
Particle size 40μm, gel fraction 90% by weight, Sekisui Plastics
Company name, trade name “Techpolymer MBX-40”, hereinafter “M
BX-40 ") or (average particle size 4 μm, gel
90% by weight, manufactured by Sekisui Plastics Co., Ltd.
Rimmer MB-4C ”, hereinafter“ MB-4C ”)
Bridge polystyrene fine particles (average particle size 8 μm, gel fraction 8
0% by weight, manufactured by Sekisui Plastics Co., Ltd.
SBX-8 ”, hereafter“ SBX-8 ”) or (flat
Uniform particle size 200μm, gel fraction 80% by weight, Sumitomo Chemical
Trade name “Fine Pearl PB-3200”
Except for using "PB-3200" below)
A thermopolymerizable composition was obtained in the same manner as in Example 1. (Preparation of Acrylic Adhesive Sheet) Screw extruder Self-wiping type three-row screw d that performs the polymerization process
The element consisting of the element and the kneading disc element
Clew (diameter; 29mm, L / D; 30) and 4 divisions
Engagement type co-rotating two-axis type with cylinder barrel
Clew Extruder (trade name “PCM”, manufactured by Ikegai Iron and Steel Co., Ltd.)
30-30-2V ”, hereafter“ PCM30 ”)
At the end, a trapezoidal 4-thread screw (straight
Diameter: 50mm, L / D: 25) and 4-part cylinder bar
Full-meshing type bidirectional rotating twin screw with barrel
Extruder (trade name “SLM50” manufactured by Sekisui Koki Co., Ltd.)
S ", hereinafter referred to as" SLM50S ").
17cm wide and 1mm thick sheet at the tip of LM50S
Connect the coat hanger die adjusted to a
Was. At this time, the SLM50S is divided into four parts.
From the upstream side, the first barrel and the second barrel
Barrel, 3rd barrel, 4th barrel, opening of 2nd barrel
PCM30 in the section, a straight tube with a heater (diameter: 10
mm, length; 180 mm). In addition,
1 barrel has rear vent a, 3rd barrel and 4th barrel
Front vents b and c are attached to the
Each vent is directly connected to the vacuum line,
A tandem extruder of the mold was obtained. [0069] Polymerization process The PCM 30 in the twin tandem extruder
1 barrel at 70 ° C, 2nd barrel at 100 ° C, 3rd barrel
And the fourth barrel is 150 ° C., and the screw rotation speed is 90.
rpm and the inside of the straight tube with heater is 150
° C, the first and second barrels of the SLM50S are
130 ° C, third and fourth barrels at 150 ° C,
After setting the screw rotation speed to 25 rpm,
Pump (manufactured by Chuo Rika Co., Ltd., trade name "VC-102M")
ODEL 186-346 ") and Examples 1 to 5 and
And the above thermopolymerizable compositions of Comparative Examples 1 to 6 were respectively continuous.
Feed and bulk polymerization was performed. [0070] Demonomerization process The rear vent a of the SLM50S is set to 100 mmHg,
Front vents b and c are each maintained at 60 mmHg.
To carry out a demonomerization step. (Production of Sheet-shaped Acrylic Adhesive Sheet
When the above process has reached a steady state,
Discharged from the coat hanger die at the tip of SLM50S
Release the acrylic adhesive sheet shaped into a sheet
38 μm thick polyethylene terephthalate treated
Laminated on film (PET film) and irradiated with electron beam
Equipment (manufactured by Nissin High Voltage, product name "Curetron"
EBC-200-20-30 ”) within 10 Mrad
Irradiate the wire with an acrylic viscosity of 1.0 ± 0.1 mm.
A wearing sheet was obtained. The evaluation items and evaluation methods are shown below. (Moldability) Visual observation of the surface properties of each acrylic pressure-sensitive adhesive sheet
Observe and mark those with marked surface roughness as "poor".
Other than the above, "good" was set, and the measurement results are shown in Tables 1 to 4. (Measurement of Amount of Residual Monomer and Conversion)
A predetermined amount of the acrylic pressure-sensitive adhesive sheet (W _a ) Remains in
BA amount (W _BA ) And 2EHA amount (W _2EHA ), The internal marker
Measured by gas chromatography (GC) using the quasi-method
However, for convenience, the amount of residual monomer and the conversion
The rate was determined. -Residual monomer amount (%) = 100 x (W _BA + W _2EHA )
/ W _a Conversion rate (%) = [1- (W _BA + W _2EHA ) / W _a ] ×
100 The above internal standard is 2-ethylhexyl methacrylate
The column is PEG20M, and the GC measurement device is "G
C-14A ”and FID detector (both Shimadzu Corporation)
(Manufactured by K.K.) in accordance with the specified conditions of use.
did. The measurement results of the conversion are shown in Tables 1 to 4. (Measurement of shear strength)
After cutting the sheet to a width of 20 mm and a length of 10 mm,
On the surface, a primer (manufactured by 3M, trade name "C-100")
SUS plate with a thickness of 2 μm (width 25 mm, length
50 mm, thickness 2 mm) under the condition of 23 ° C.
300mm / min speed using 2kg pressure roller
2 times reciprocating at a temperature and stuck together for 24 hours at room temperature
A test piece was obtained by leaving it to stand. How to shear the above test piece
Direction by pulling at a speed of 50 mm / min.
The results of measuring the shear strength are shown in Tables 1 to 4. Unit is kg
f / cm ^Two It is. (Measurement of T-peel strength)
After cutting to 20mm and 70mm in length,
Aluminum foil coated with the primer to a thickness of 2 μm (Japan
Made by Test Panel, part number "1100P", JIS H4
000 standard product, 30mm x 100mm x 0.03mm)
Is applied at 23 ° C, and a 2 kg pressure roller is
Reciprocate two times at a speed of 300 mm / min.
Combined and left for 24 hours at room temperature for testing
I got a piece. The above test piece was subjected to JIS K685 at room temperature.
T-peel strength at 200 mm / min speed
Are shown in Tables 1 to 4. The unit is kgf / 2
The width is 0 mm. [Table 1] [Table 2] [Table 3] [Table 4] The acrylic pressure-sensitive adhesive sheet of the present invention
Certain fine particles have a higher modulus of elasticity compared to ril-based copolymers.
High shear strength due to dispersed particle filler
Sufficient peel strength to effectively disperse the stress at separation
It is expensive. For this reason, heavy load applications
Suitable for use as a base material for double-sided
It can be used appropriately, and such a double-sided adhesive
The loop is easier to handle than the adhesive, so the bonding of various structures
Business can be performed easily.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-113603 (JP, A) JP-A-8-53597 (JP, A) JP-A-8-60118 (JP, A) JP-A-60-1985 219203 (JP, A) JP-A-58-53970 (JP, A) Table 10-508636 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 2/00-2 / 60 C09J 7/00

Claims (1)

(57) [Claim 1] 100 parts by weight of a vinyl-based mixed monomer composed of (A) an alkyl (meth) acrylate and (B) a vinyl monomer having a polar group, the following (C) to (F) No
A method for producing an acrylic pressure-sensitive adhesive sheet, comprising supplying a thermopolymerizable composition comprising at least one of the above and a thermal decomposition type radical polymerization initiator into a screw extruder and performing heat polymerization. (C) Porous inorganic fine particles having an average particle size of 100 μm or less
0.5 to 20 parts by weight (D) Flat inorganic fine particles 1 to 2 having an average diameter of 50 μm or less
5 parts by weight (E) non-polar organic fine particles 5 having an average particle size of 1 to 100 μm
80 parts by weight (F) having an average particle size of 6~100μm crosslinked organic fine particles 5
70 parts by weight