JP3313132B2 - Surface protection adhesive film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to deep drawing and multi-step drawing of stainless steel, aluminum and other metal plates.
The present invention relates to a surface protective pressure-sensitive adhesive film temporarily attached to the surface of the metal plate.

[0002]

2. Description of the Related Art A surface protective adhesive film is known in which an adhesive layer is provided on one side of a plastic film base material such as polyethylene, polypropylene, polyvinyl chloride, etc. for protecting the surface of a stainless steel plate, an aluminum plate, a color steel plate or the like. I have. Generally, even when processing a metal plate lightly, these surface protective adhesive films are used to prevent surface damage, but for advanced metal plate processing such as deep drawing, multi-stage drawing, etc. No surface protective pressure-sensitive adhesive film has satisfactory performance. That is, in advanced drawing processing, the adhesive force to the surface of the metal plate cannot withstand the stress of the base film generated during processing, and the pressure-sensitive adhesive film peels off from the surface of the metal plate immediately after processing or over time (generally, It is called "floating".)
This is because the floating easily causes damage to the metal plate surface in the next processing step.

Therefore, in advanced metal sheet processing, means such as coating and baking a polyvinyl chloride-based paint on the metal sheet surface or heat-sealing a heat-sensitive film having no tack at room temperature is used. ing. However, these means lack the simplicity of the temporary protective work as compared with the surface protective adhesive film, and there is an urgent need to develop a surface protective adhesive film that can be used for advanced metal plate processing.

[0004] Conventionally, in order to suppress the occurrence of floating in the surface protective pressure-sensitive adhesive film, proposals have been made regarding the development of a pressure-sensitive adhesive layer having sufficient adhesiveness to the surface of the metal plate to withstand the stress generated in the substrate film. However, it has not yet reached a satisfactory level. These proposals relate to a pressure-sensitive adhesive layer to which a tackifier resin or the like has been added to improve the adhesiveness to a metal plate surface, or a pressure-sensitive adhesive layer having a higher molecular weight or a higher glass transition temperature. .

[0005] However, in the former, since the peel strength from the surface of the metal plate is too high, the re-peelability of the surface protective film becomes poor after processing or after being stored for a long time after temporary attachment, so that practical use is not possible. It was inconvenient. Also, in the latter, the initial adhesive strength at room temperature is extremely low,
There was a problem in practical use, such as the end portion being easily peeled off immediately after temporary attachment. That is, in order to suppress the occurrence of floating in advanced metal plate processing, it was necessary to sacrifice the basic performance required for the surface protective adhesive film.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a surface protective pressure-sensitive adhesive film which can overcome the above-mentioned problems of the prior art and can be applied to advanced metal plate processing.

[0007]

Means for Solving the Problems The present inventors have focused on the fact that the aqueous dispersion is a heterogeneous system in order to achieve the above object, and as a result of diligent studies, have found that two types of copolymers having a specific composition are obtained. The pressure-sensitive adhesive layer obtained from the aqueous dispersion-type pressure-sensitive adhesive composition in which the particles are mixed in a specific ratio has the basic performance required as a surface protective pressure-sensitive adhesive film, and suppresses floating in advanced metal plate processing such as deep drawing. Was found to be extremely effective, and resulted in the present invention.

That is, the present invention relates to a surface protective pressure-sensitive adhesive film comprising a plastic film provided with a pressure-sensitive adhesive layer on one side, wherein the pressure-sensitive adhesive layer is formed of methyl acrylate or ethyl acrylate.
Relate, propyl acrylate, butyl acrylate
G, hexyl acrylate, octyl acrylate,
Group consisting of nyl acrylate and dodecyl acrylate
At least one alkyl S. <br/> Terumonoma acrylate are al selected using as the main constituent monomers, acrylic
Acid, methacrylic acid, crotonic acid, itaconic acid, maleic
Acid, hydroxyethyl fumarate acrylate, acrylic
Amide, methacrylamide, dimethylaminoethyl
Relate, dimethylaminoethyl methacrylate, acetic acid
Select from the group consisting of vinyl, styrene, and acrylonitrile
At least one vinyl monomer selected for copolymerization
Manufactured by emulsion polymerization method
(A, B) having a glass transition temperature of -2
An aqueous dispersion of the copolymer A having a temperature of less than 0 ° C. and a gel content of 70% by weight or more;
0 to 50 ° C., and the gel content is 5 to 60% by weight
And an aqueous dispersion of the copolymer B, each having a mixing ratio of 30 to 95% by weight for the copolymer A and 7 for the copolymer B.
A surface protective pressure-sensitive adhesive film obtained from an aqueous dispersion mixture of 0 to 5% by weight.

The aqueous dispersion used in the present invention is obtained by emulsion polymerization of an alkyl (meth) acrylate monomer and a vinyl monomer copolymerizable therewith. Examples of the alkyl (meth) acrylate monomer include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, hexyl acrylate, hexyl methacrylate, octyl acrylate, octyl methacrylate, and nonyl. Examples thereof include acrylate, nonyl methacrylate, dodecyl acrylate, and dodecyl methacrylate. The side chain alkyl group may be linear or branched. Further, two or more of the above-mentioned alkyl (meth) acrylate monomers may be used in combination depending on the purpose.

Examples of the vinyl monomer copolymerizable with the alkyl (meth) acrylate monomer include, for example,
Acrylic acid, methacrylic acid, crotonic acid, itaconic acid,
Maleic acid, hydroxyethyl fumarate acrylate,
Examples include hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, acrylamide, methacrylamide, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, vinyl acetate, styrene, acrylonitrile, and the like.

In the present invention, these vinyl monomers may be appropriately selected so that the glass transition temperature of the copolymer becomes a predetermined value. That is, in the copolymer A, its glass transition temperature should be lower than −20 ° C., preferably −70 ° C. to −20 ° C., and more preferably −60 ° C. to −30 ° C. is there. Glass transition temperature is -2
When the temperature is 0 ° C. or higher, the initial adhesive strength at room temperature is insufficient, which is a practical problem. Further, in the copolymer B, its glass transition temperature should be -20 ° C to 50 ° C, preferably -20 ° C to 40 ° C, more preferably -10 ° C to 30 ° C. is there. Glass transition temperature is 50 ℃
Exceeds -20 ° C, the initial adhesive strength at room temperature is insufficient.
Otherwise, the suppression of the floating is not achieved.

Further, the gel content of the copolymer used in the present invention is controlled by controlling the above-mentioned vinyl monomer mixture.
It is most convenient to add an appropriate amount of a crosslinking monomer or a chain transfer agent and carry out emulsion polymerization. Crosslinkable monomers include divinylbenzene, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate,
Examples include polyfunctional monomers such as trimethylolpropane triacrylate and trimethylolpropane trimethacrylate, and internal crosslinking monomers such as N-methylolacrylamide, N-methylolmethacrylamide, glycidyl acrylate, and glycidyl methacrylate. Examples of the chain transfer agent include lower alcohols such as methanol and ethanol, carbon tetrachloride, nitrobenzene, thioglycolic acid, thioglycol-2-ethylhexylate, dodecyl mercaptan, octyl mercaptan, lauryl disulfide, and the like.

In terms of the gel content of the copolymer used in the present invention, copolymer A must be at least 70% by weight. Preferably, it is at least 80% by weight. If it is less than 70% by weight, the removability is poor, which is a practical problem. Also, copolymer B must be 5 to 60% by weight. Preferably, it is 10 to 50% by weight. If the amount is less than 5% by weight, suppression of lifting and good removability cannot be achieved, and if it exceeds 60% by weight, the initial tackiness becomes insufficient.

The emulsion polymerization method for obtaining the aqueous dispersion used in the present invention is not particularly limited, but by specifying the particle size of the aqueous dispersion, the effects of the present invention can be further exerted. Therefore, it is preferable to control the particle diameter by a conventionally known seed polymerization method. The average particle diameter of the aqueous dispersion particles is preferably 0.01 μm to 3 μm.
If the average particle size is extremely small, the viscosity of the aqueous dispersion becomes extremely high, which is inconvenient in handling. If the average particle size is extremely large, the stability of the particles becomes poor, which is a problem in production and storage. In order to further exert the effects of the present invention, the average particle size of the copolymer B is preferably larger than the average particle size of the copolymer A, and more preferably the average particle size of the copolymer B is That is, the average particle diameter is at least twice as large as the average particle diameter of the combined particles A.

The mixing ratio of the aqueous dispersion mixture used in the present invention is such that the mixing ratio of the copolymer A is 30 to 95% by weight,
Unless the mixing ratio of the copolymer B is 70 to 5% by weight, the effect of the present invention is not exhibited. Preferably, the mixing ratio of the copolymer A is 40 to 90% by weight, and the mixing ratio of the copolymer B is 6%.
The mixing ratio of the copolymer A is 50 to 80% by weight, and the mixing ratio of the copolymer B is 50 to 20% by weight. When the mixing ratio of the copolymer A is 30
If it is less than 10% by weight, the initial adhesive strength at room temperature is insufficient, and
If it exceeds 5% by weight, the effect of suppressing floating is not exhibited.

In the present invention, the aqueous dispersion obtained by the above method can be used directly as a pressure-sensitive adhesive composition. However, as long as the effects of the present invention are not impaired, various conventionally known external crosslinking agents and pressure-sensitive adhesives can be used. Giving agents can also be included. If necessary, a thickener, a film-forming aid, an antifoaming agent, and the like may be added.

The plastic film used in the present invention includes a polyethylene film, a polypropylene film, a polyvinyl chloride film and the like.
The thickness is preferably 30 to 150 μm, although it varies depending on the application.

The production of the surface protective film of the present invention can be obtained by applying the above aqueous dispersion pressure-sensitive adhesive composition to one side of a plastic film by a known method, followed by drying and providing a pressure-sensitive adhesive layer.

According to the present invention, a surface protection pressure-sensitive adhesive film which is impossible with the prior art, that is, which is applicable to advanced metal plate processing such as deep drawing and multi-step drawing and has excellent basic performance. Can be obtained.

[0020]

The present invention will be described below in detail with reference to examples. In the following, parts are parts by weight, and% is% by weight.
Is shown. The average particle size of the copolymer particles, the glass transition temperature of the copolymer, the measurement of the gel content, and the performance evaluation of the surface protective pressure-sensitive adhesive film were performed by the following methods.

<Average Particle Diameter> The measurement was performed using a submicron particle analyzer N4SB type (manufactured by Coulter Electronics Co., Ltd.).

<Glass Transition Temperature> The glass transition temperature was measured by a conventional method using a differential scanning calorimeter from -150 ° C. at a heating rate of 10 ° C./min.

<Gel Content> A filter paper impregnated with 2 g of the aqueous dispersion was dried at room temperature under reduced pressure, and then dried in toluene.
Immerse in 0 ml for 24 hours. After immersion, the toluene solution containing the soluble component of the copolymer was evaporated, and the following formula [Equation 1] was obtained.

[0024]

(Equation 1) Was used to determine the gel content. Weight of filter paper and copolymer (non-volatile content in aqueous dispersion) after drying under reduced pressure: A Weight of residue (toluene-soluble component in copolymer) after distillation of toluene: B Weight of filter paper: C

<Drawability> Under an atmosphere of 23 ° C., a surface protective adhesive film was formed of SUS3 having a thickness of 0.6 mm.
Laminator (pressure 1kg / c)
m ² ) and left for 24 hours, then 80m in diameter
m, and a drawing test was performed by the processing method shown in FIG. In FIG. 1, the shape of the punch bottom is a round radius 3R of 3 mm, a punch diameter of 35 mm, a die hole diameter of 37 mm, and a die shoulder radius 3R of 3 m.
m. Also, the drawing depth is 12 mm, and the drawing speed is
Drawing was performed at 5 mm / min. For the evaluation, the time required for the length of the float generated in the flange portion (A portion) to reach 3 mm toward the center after drawing was measured.

<Adhesive force> In an atmosphere of 23 ° C., a surface protective film was bonded to a SUS304 mirror-finished plate with a laminator (pressure 1 kg / cm ² ), left under predetermined conditions, and peeled at an angle of 180 ° and a speed of 300 mm. The stress at the time of peeling was measured at a rate of / mm and converted to a film width of 25 mm.

Initial adhesion: measured after standing at 23 ° C. for 30 minutes Adhesion after heating: measured after standing at 60 ° C. for 7 days

Production Example 1 500 parts of ion-exchanged water, 1.5 parts of potassium persulfate and 1.2 parts of sodium lauryl sulfate were placed in a reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube and a reflux condenser. And heated to 70 ° C. under a nitrogen atmosphere, then butyl acrylate 89%, acrylonitrile 4%, methacrylic acid 2
%, And 500 parts of a monomer mixture consisting of 5% ethylene glycol dimethacrylate were continuously added over 5 hours.
By holding at 75 ° C. for 3 hours, the average particle size is reduced to 0.1.
15 μm, glass transition temperature -41 ° C., gel content 9
An aqueous dispersion 1 of 2% was obtained.

Production Example 2 In Production Example 1, the composition of the monomers was changed to 91% of butyl acrylate, 4% of acrylonitrile, 2% of methacrylic acid, and 3% of hydroxyethyl methacrylate. Further, 500 parts of the monomer mixture was added to n-dodecyl mercaptan. By adding 1.5 parts, an aqueous dispersion 2 having an average particle size of 0.17 μm, a glass transition temperature of −45 ° C., and a gel content of 40% was obtained.

Production Example 3 In Production Example 1, the average particle diameter was changed to 0.35 by adding 0.8 parts of sodium lauryl sulfate.
μm, glass transition temperature -42 ° C, gel content 85%
Was obtained.

Production Example 4 In Production Example 1, sodium lauryl sulfate was added in an amount of 0.4%.
Parts, the composition of the monomer is 55% butyl acrylate, 20% methyl methacrylate, 20% styrene, 2 acrylic acid
%, Hydroxyethyl methacrylate 3%, and
An aqueous dispersion having an average particle diameter of 0.67 μm, a glass transition temperature of 1 ° C., and a gel content of 23% was obtained by adding 3.5 parts of t-dodecyl mercaptan to 500 parts of the monomer mixture. 4 was obtained.

Production Example 5 In Production Example 4, the composition of the monomers was 55% butyl acrylate, 20% methyl methacrylate, 17% styrene,
Acrylic acid 2%, hydroxyethyl methacrylate 3
%, 3% divinylbenzene, and further, without adding t-dodecyl mercaptan, to obtain an aqueous dispersion 5 having an average particle diameter of 0.65 μm, a glass transition temperature of 5 ° C., and a gel content of 85%. I got

Production Example 6 The procedure of Production Example 4 was repeated, except that sodium lauryl sulfate was changed to 1.5 parts so that the average particle diameter was 0.15.
An aqueous dispersion 6 having a particle size of 35 μm, a glass transition temperature of 5 ° C. and a gel content of 35% was obtained.

Production Example 7 In Production Example 1, sodium lauryl sulfate was added in an amount of 0.2%.
Parts, the composition of the monomer is 2 ethylhexyl acrylate 30
%, Methyl acrylate 10%, methyl methacrylate 35
%, Styrene 20%, acrylic acid 3%, hydroxyethyl methacrylate 2%, and a monomer mixture 50%.
By adding 5.0 parts of t-dodecyl mercaptan to 0 parts, the average particle diameter becomes 0.70 μm.
m, a glass transition temperature of 21 ° C., and an aqueous dispersion 7 having a gel content of 15%.

Preparation Example 8 In Preparation Example 1, the composition of the monomers was changed to 2-ethylhexyl acrylate 65%, methyl methacrylate 10%, vinyl acetate 15%, methacrylic acid 2%, hydroxyethyl methacrylate 3%, acrylamide 2%, glycidyl methacrylate By making a change to 3%, an aqueous dispersion 8 having an average particle diameter of 0.12 µm, a glass transition temperature of -32 ° C, and a gel content of 91% was obtained.

Production Example 9 In Production Example 1, sodium lauryl sulfate was added in an amount of 0.2%.
Parts and 30% of acrylonitrile, 30% of methyl methacrylate, 30% of methyl acrylate, 5% of methacrylic acid and 5% of hydroxyethyl methacrylate. Further, 500 parts of the monomer mixture and 4.0 parts of n-octyl mercaptan were used. The average particle diameter is 0.85 μm and the glass transition temperature is 7
An aqueous dispersion 9 at 1 ° C. and a gel content of 23% was obtained.

Production Example 10 In Production Example 1, sodium lauryl sulfate was added in an amount of 0.4%.
Parts, the composition of the monomer was 55% of butyl acrylate, 20% of methyl methacrylate, 20% of styrene, and 5% of hydroxyethyl methacrylate.
By adding 5.0 parts of t-dodecyl mercaptan to 0 parts, the average particle diameter becomes 0.73 μm.
m, a glass transition temperature of -1 ° C, and an aqueous dispersion 10 having a gel content of 3%.

Production Example 11 In Production Example 1, the composition of the monomers was changed to 67% of butyl acrylate, 20% of methyl methacrylate, 10% of acrylonitrile, 1% of acrylic acid, and 2% of N-methylolacrylamide. An aqueous dispersion 11 having an average particle size of 0.20 μm, a glass transition temperature of −17 ° C., and a gel content of 91% was obtained.

Example 1 The aqueous dispersion 1 and the aqueous dispersion 4 obtained in the above Production Examples were mixed so that the weight ratio of the copolymer was 60:40. The product was treated on a treated surface of a polyethylene film (thickness: 50 μm, density: 0.92, melt index: 8.0) having one surface subjected to corona discharge treatment.
It was applied and dried using a reverse roll coater so that the thickness after drying was 10 μm, and a surface protective adhesive film was obtained. The performance evaluation results are shown in [Table 1].

Example 2 The aqueous dispersion 8 and the aqueous dispersion 7 were mixed so that the weight ratio of the copolymer was 70:30, and 100 parts of the aqueous dispersion mixture was used as a crosslinking agent as a crosslinking agent. The performance of a surface protective pressure-sensitive adhesive film obtained in the same manner as in Example 1 from an aqueous dispersion-type pressure-sensitive adhesive composition containing 1 part of trimethylolpropane polyglycidyl ether was evaluated. The results are shown in Table 1.
Shown in

Example 3 An aqueous dispersion-type pressure-sensitive adhesive composition in which the aqueous dispersion 1 and the aqueous dispersion 6 were mixed so that the weight ratio of the copolymer was 60:40 was obtained in the same manner as in Example 1. The performance of the obtained surface protective pressure-sensitive adhesive film was evaluated. The results are shown in [Table 1].

Example 4 An aqueous dispersion-type pressure-sensitive adhesive composition in which the aqueous dispersion 3 and the aqueous dispersion 6 were mixed so that the weight ratio of the copolymer was 60:40 was obtained in the same manner as in Example 1. The performance of the obtained surface protective pressure-sensitive adhesive film was evaluated. The results are shown in [Table 1].

Example 5 An aqueous dispersion-type pressure-sensitive adhesive composition in which the aqueous dispersion 1 and the aqueous dispersion 4 were mixed so that the weight ratio of the copolymer was 90:10 was obtained in the same manner as in Example 1. The performance of the obtained surface protective pressure-sensitive adhesive film was evaluated. The results are shown in [Table 1].

Example 6 An aqueous dispersion-type pressure-sensitive adhesive composition obtained by mixing aqueous dispersion 1 and aqueous dispersion 4 such that the weight ratio of the copolymer was 35:65 was obtained in the same manner as in Example 1. The performance of the obtained surface protective pressure-sensitive adhesive film was evaluated. The results are shown in [Table 1].

Comparative Example 1 An aqueous dispersion-type pressure-sensitive adhesive composition in which the aqueous dispersion 1 and the aqueous dispersion 4 were mixed so that the weight ratio of the copolymer was 97: 3 was obtained in the same manner as in Example 1. The performance of the obtained surface protective pressure-sensitive adhesive film was evaluated. The results are shown in [Table 1].

Comparative Example 2 An aqueous dispersion type pressure-sensitive adhesive composition was prepared by mixing aqueous dispersion 1 and aqueous dispersion 4 such that the weight ratio of the copolymer was 20:80, in the same manner as in Example 1. The performance of the obtained surface protective pressure-sensitive adhesive film was evaluated. The results are shown in [Table 1].

Comparative Example 3 The aqueous dispersion 8 and the aqueous dispersion 9 were mixed so that the weight ratio of the copolymer was 70:30, and 100 parts of the aqueous dispersion mixture was used as a crosslinking agent. The performance of a surface protective pressure-sensitive adhesive film obtained in the same manner as in Example 1 from an aqueous dispersion-type pressure-sensitive adhesive composition containing 1 part of trimethylolpropane polyglycidyl ether was evaluated. The results are shown in Table 1.
Shown in

Comparative Example 4 The aqueous dispersion 11 and the aqueous dispersion 7 were mixed so that the weight ratio of the copolymer was 70:30, and 100 parts of the aqueous dispersion mixture was used as a crosslinking agent. The performance of a surface protective pressure-sensitive adhesive film obtained in the same manner as in Example 1 from an aqueous dispersion-type pressure-sensitive adhesive composition containing 1 part of trimethylolpropane polyglycidyl ether was evaluated. The results are shown in [Table 1].

Comparative Example 5 An aqueous dispersion type pressure-sensitive adhesive composition obtained by mixing aqueous dispersion 1 and aqueous dispersion 5 such that the weight ratio of the copolymer was 60:40 was obtained in the same manner as in Example 1. The performance of the obtained surface protective pressure-sensitive adhesive film was evaluated. The results are shown in [Table 1].

Comparative Example 6 An aqueous dispersion-type pressure-sensitive adhesive composition in which the aqueous dispersion 2 and the aqueous dispersion 4 were mixed so that the weight ratio of the copolymer was 60:40 was obtained in the same manner as in Example 1. The performance of the obtained surface protective pressure-sensitive adhesive film was evaluated. The results are shown in [Table 1].

Comparative Example 7 An aqueous dispersion-type pressure-sensitive adhesive composition in which the aqueous dispersion 1 and the aqueous dispersion 10 were mixed so that the weight ratio of the copolymer was 60:40 was obtained in the same manner as in Example 1. The performance of the obtained surface protective pressure-sensitive adhesive film was evaluated. The results are shown in [Table 1].

Comparative Example 8 An aqueous dispersion type pressure-sensitive adhesive composition in which the aqueous dispersion 1 and the aqueous dispersion 11 were mixed so that the weight ratio of the copolymer was 60:40 was obtained in the same manner as in Example 1. The performance of the obtained surface protective pressure-sensitive adhesive film was evaluated. The results are shown in [Table 1].

[0053]

[Table 1]

[0054]

According to the present invention, a surface protective pressure-sensitive adhesive film having excellent basic performance and applicable to advanced metal plate processing can be obtained. That is, in Comparative Examples 1 and 5, which are out of the range of the present invention, the change with time in the adhesive strength is small, but the drawability is poor. Further, Comparative Examples 2, 3, and 4 have an extremely low initial adhesive strength and are not practical. Further, Comparative Examples 6, 7, 8
Has a large increase in adhesive strength over time and has poor drawability. In contrast, Examples 1, 2, 3,
Nos. 4, 5, and 6 show little change with time in the adhesive strength and are excellent in drawability. Therefore, the present invention has made it possible to provide a high-performance pressure-sensitive surface protection film for drawing in both basic performance and drawability.

[Brief description of the drawings]

FIG. 1 is a partially enlarged sectional view of an Elexen test apparatus for evaluating drawability.

[Explanation of symbols]

 1 ... Surface protective adhesive sheet as a sample 2 ... Stainless steel plate as an example of an adherend A ... A part where floating occurs first after drawing

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-124783 (JP, A) JP-A-2-194,811 (JP, A) JP-A-5-171120 (JP, A) JP-A-61- 103574 (JP, A) JP-A-5-86346 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09J 1/00-201/10

Claims (4)

(57) [Claims] 1. A surface protective pressure-sensitive adhesive film comprising a plastic film provided with a pressure-sensitive adhesive layer on one side, wherein the pressure-sensitive adhesive layer is formed of methyl acrylate, ethyl acrylate,
Pill acrylate, butyl acrylate, hexyl acrylate
Related, octyl acrylate, nonyl acrylate
And dodecyl acrylate.
Without even used in the one acrylic acid alkyl ester monomer as a main constituent monomer, acrylic acid, methacrylic
Acid, crotonic acid, itaconic acid, maleic acid, fumaric acid
Droxyethyl acrylate, acrylamide, methac
Lilamide, dimethylaminoethyl acrylate, dye
Tylaminoethyl methacrylate, vinyl acetate, styrene
, Selected from the group consisting of acrylonitrile
And one type of vinyl monomer as a vinyl monomer for copolymerization
Used as a copolymer produced by an emulsion polymerization method
(A, B), an aqueous dispersion of copolymer A having a glass transition temperature of less than −20 ° C. and a gel content of 70% by weight or more; 50 ℃
And an aqueous dispersion of the copolymer B having a gel content of 5 to 60% by weight, the mixing ratio of each being 30 to 95% by weight of the copolymer A and 70 to 70% by weight of the copolymer B. A surface-protective pressure-sensitive adhesive film, which is obtained from an aqueous dispersion mixture of about 5% by weight. 2. Methyl methacrylate, ethyl methacrylate
, Propyl methacrylate, butyl methacrylate
G, hexyl methacrylate, octyl methacrylate
G, nonyl methacrylate, dodecyl methacrylate
At least one methacrylic acid selected from the group consisting of
The alkyl ester monomer is converted to an alkyl acrylate
Claims characterized in that they are used together with a termonomer.
2. The surface protective pressure-sensitive adhesive film according to 1. 3. Divinylbenzene, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, trimethylolpropane triacrylate,
At least one crosslinking monomer selected from the group consisting of trimethylolpropane trimethacrylate, N-methylolacrylamide, N-methylolmethacrylamide, glycidyl acrylate and glycidyl methacrylate, or a lower alcohol, carbon tetrachloride, nitrobenzene, thioglycolic acid , Thioglycol-2-
Ethylhexylidene carboxylate, dodecyl mercaptan, octyl mercaptan, one surface protective adhesive film according to claim 1, wherein the use of chain transfer agent and less selected from the group consisting of lauryl disulfide. 4. An acrylic acid alkyl ester monomer
Methacrylic acid alkyl ester monomer and acrylic
Acid methacrylate monomer, alkyl methacrylate
Total amount of ster monomer and vinyl monomer for copolymerization
75 to 89 parts by weight for 100 parts by weight
4. The surface protective adhesive according to claim 2, wherein
Wearing film.