JPS6147772A - Resin composition for pressure-sensitive adhesive - Google Patents

Abstract

PURPOSE:The titled composition for a film which protects the surface of a material temporarily, having a small change in bond strength with time, and improved releasing workability, obtained by blending a high-molecular-weight acrylic polymer with an acrylic polymer with a specific molecular weight range in a specific ratio. CONSTITUTION:(A) 60-95wt% acrylic polymer having >=200,000 weight-average molecular weight with (B) 5-40wt% acrylic polymer having 1,500-30,000, preferably 2,000-15,000 weight-average molecular weight, to give the aimed composition. A blending ratio of 65-90wt% polymer A and 10-35wt% polymer B is more preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the invention (industrial application field) The present invention provides adhesives, particularly stainless steel plates, aluminum plates,
Resin composition for adhesives for surface protection films that temporarily protect the surfaces of metal plates such as steel plates, painted metal plates, or non-metallic objects such as A2B plates, acrylic plates, styrene plates, decorative plates, glass plates, and wooden plates. The present invention relates to a pressure-sensitive adhesive resin composition, in particular, which exhibits little change in adhesive strength over time during the period of application and has excellent peelability.

[Conventional technology]

A surface protection film is applied to the surface of a plate-shaped object such as the one described above, and is protected against dust, chemicals, sunlight, and other objects during transportation and storage.
It is used to prevent scratches, contamination, discoloration, stains, etc. from occurring on the surface of these plate-shaped objects due to the effects of wind and rain.

It is also used to improve workability and prevent scratches on the metal plate by attaching it to the metal plate when processing the metal plate, such as embossing, bending, punching, etc.

After achieving the above purpose, it is necessary to be able to easily peel it off from the surface of the plate-like object.

It is manufactured through processes such as drying.

Among these adhesives, acrylic adhesives made of aluminum acrylate have high resistance to light and air, and excellent transparency, so they are most suitable for the above uses. In order to be used for practical purposes, it is also necessary to have the following characteristics.

(1) It must have adhesion strength to the protected surface of various plate-like objects according to its use and purpose. It is not preferable to use a material whose adhesive strength is so low that it is difficult to adhere to the surface to be protected.

(2) Its adhesive strength hardly changes orally, and the surface protection film can be easily peeled off from the protected surface.

(3) There should be no contamination or transfer of adhesive to the protected surface after peeling.

(4) When used for processing metal plates such as embossed, bent, punched, etc., the material peeled off from the metal plate during the processing should not be lifted up.

Up until now, such surface protection films have been made using acrylic adhesive compositions with a weight average molecular weight of 200,000.
0 or more is used, but if it is pasted on the protected surface of a plate-shaped object and stored for a long period of time, the adhesive strength increases when administered orally, making it difficult to peel off, or even if it does not peel off. Even if it were possible, there were drawbacks such as contamination of the surface to be protected of the plate-shaped object and large amount of adhesive transferred.

This may be due to an increase in the contact area between the surface protection film and the surface to be protected, or the adhesion may be due to curing or deterioration of the acrylic adhesive due to light such as ultraviolet rays or heat.

In order to solve these drawbacks, attempts have been made to use hard acrylic polymers with a high glass transition point and to increase the amount of crosslinking agent in the acrylic adhesive. However, although such attempts can be easily peeled off, the adhesive strength is extremely low, making it difficult to attach to various plate-shaped objects, or surface protection during metal plate processing. This is not desirable because the film may peel off and come to the surface. In addition, silicone compositions, surfactants,
Attempts have been made to add plasticizers, etc., but this has resulted in contamination of the protected surface of the plate-shaped object or in cases where the surface protection film has peeled off during processing of the metal plate. I don't like it because it makes me slurp.

[Problems to be Solved by the Invention] The present inventors have carried out intensive research in order to solve these drawbacks and further satisfy the above-mentioned required properties. By mixing an appropriate amount of a low-strength acrylic polymer, the initial adhesive strength can be maintained at a suitable level, and the adhesive strength can be changed during the application period without impairing the workability of pasting it on a metal plate. The present inventors have discovered the unexpected effect of producing an excellent surface protection film that exhibits excellent peeling workability and no staining or transfer of adhesive to the surface to be protected after peeling, and has now completed the present invention.

That is, in the present invention, the weight average molecular weight IJ=2oo, o
7. Concerning an adhesive composition comprising 60 to 95% by weight of an acrylic polymer having a weight average molecular weight of 1.500 to 3α000 and 5 to 40% by weight of an acrylic polymer having a weight average molecular weight of 1.500 to 3α000. The present invention particularly relates to a resin composition for adhesives that is excellent for use in surface protection films.

(2) Structure of the Invention [Weight Average Molecular Weight] The weight average molecular weight in the present invention is the weight average molecular weight in terms of polystyrene, which is determined as follows.

Measurement method Gel Permeation Chromatography
phy (abbreviation GPC) Sample concentration Solid content concentration 0.51/10031/N, diluted with tetrahydrofuran - Equipment name Toyo Soda Co., Ltd. - HLO-801, A column Toyo Soda Co., Ltd. T8 - GELH Type GMHH66
0 wounds x 7.5 Omit and calculate. The chromatogram is divided into approximately 20 to 40 points, and the weight average molecular weight in terms of polystyrene is calculated using the following formula, and this is defined as the weight average molecular weight in the present invention.

,=DH4Mi W -111111H4 Where, MW: Weight average molecular weight in terms of polystyrene H2 The height unit from the baseline to the chromatogram at the two-division point i is either 礪 or 笪. Just use it. ) The acrylic polymer having a weight average molecular weight of 31,200.000 or more, which is the standard polystyrene molecular weight determined from the calibration curve at the two-way point 1, is a common acrylic adhesive for surface protection films, and is the main component of this composition. make up the ingredients. A more preferable range of this weight average molecular weight is 300.000 to 4,000.00.
It is 0.

Acrylic polymers with a weight average molecular weight of less than 200,000 are unsuitable because they tend to cause staining and adhesive transfer to the protected surface upon peeling, even if they are used in excess of 60 weights. In addition, in the case of acrylic polymers with a weight average molecular weight exceeding 4,000,000, there will be no problem of contamination or adhesive migration on the protected surface during peeling, but they are difficult to synthesize and have a low solidity. It is undesirable because it can only be synthesized in minutes, or because of its high viscosity, it cannot be used without dilution, and the resulting adhesive product also has a low solids content, which is undesirable.

The 7-acrylic polymer having a weight average molecular weight of 1,500 to 30,000 is added to reduce changes in adhesive strength over time, and preferably has a weight average molecular weight of 2,000 to 1.
Preferably between 5,000 and 0. Acrylic polymers with a weight average molecular weight of less than 1.500 tend to cause staining and adhesive transfer to the protected surface during peeling, even if less than 40% by weight is used. In addition, the adhesive strength is poor and the surface protective film tends to peel off and become loose when processing metal plates, making it unsuitable for use.

Furthermore, if the weight average molecular weight exceeds ao or ooo, it is difficult to achieve the effect of reducing changes in adhesive strength over time, making it impossible to achieve the objective.

[Blending ratio]

The resin composition for adhesives of the present invention has a weight average molecular weight of 200.
．． 000 or more acrylic polymer 60 to 95% by weight,
Weight average molecular weight is 1,500 to 30.00. (It consists of 5 to 40% by weight of the real acrylic polymer, but this blending ratio is based on the resin content of the composition, that is, from the composition to the solvent,
This is a value calculated based on excluding water, inorganic fillers, etc.

The mixing ratio of the former is 65 to 90% by weight, and the latter is 1% by weight.
More preferably 0 to 35% by weight.

If the amount of the acrylic polymer with a weight average molecular weight of 1.500 to 30,000 is less than 5% by weight, it will be difficult to reduce the change in adhesive strength over time, and if it exceeds 40% by weight, it will cause problems during peeling. It is easy to cause contamination and adhesive transfer to the surface to be protected, and the adhesive strength is low and the surface protection film tends to peel off or lift up when processing thin metal.
Both should be avoided.

[Acrylic polymer]

Weight average molecules constituting the adhesive resin composition of the present invention -
Acrylic polymer with t, 200.000 or more and q voice weight average molecular weight 1. Examples of the acrylic polymer having a carbon number of 181 to 30,000 include acrylates having an alkyl group of 2 to 8 carbon atoms, such as ethyl acrylate, n-butyl acrylate, i-butyl acrylate, and 2-ethylhexyl acrylate. A polymer containing at least one of these alkyl acrylates as a main component can be used, and other monomers copolymerizable with the alkyl acrylate can also be copolymerized.

Other monomers copolymerizable with the alkyl acrylate include, for example, methyl acrylate, methyl methacrylate, lauryl methacrylate, vinyl acetate, styrene,
Vinyl monomers such as acrylonidolyl, acrylic acid,
Methacrylic acid, 2-hydroxyethyl acrylate, 2
-Carboxyl group-containing monomers such as -hydroxyethyl methacrylate, glycidyl methacrylate, N-methylol acrylamide, and acrylamide, and functional group-containing monomers such as hydroxyl group, glycidyl group, and amide group.

Further, more preferable acrylic polymers constituting the adhesive resin composition of the present invention include a homopolymer of n-butyl acrylate, a copolymer of n-butyl acrylate and 2-ethylhexyl acrylate, or a copolymer of n-butyl acrylate and 2-ethylhexyl acrylate. Examples include copolymers of 111 or more monomers selected from hydroxyethyl acrylate, acrylic acid, methacrylic acid, acrylonitrile, and the like.

[Glass transition point]

The polymerization ratio of the monomer is set at 1 to avoid damaging the adhesive properties.
It may be determined based on the glass transition point (Tg point) of the polymer. The preferred Tg point for a pressure-sensitive adhesive is generally -10°C or less, and if A exceeds -10°C, the composition has poor tackiness and is not preferred as a pressure-sensitive adhesive.

In general, to actually measure the Tg point of a polymer, for example, the thermal expansion at various temperatures is measured and the Tg point is determined as the intersection of two straight lines with different slopes on the specific volume-temperature curve. There is a way.

However, for convenience, if the value of the Tg point of each homopolymer is known, then the Tg point of the copolymer can be calculated using the following formula.
You can find the point (A, V, Tobolsky
i″Property@and 8tructor
e of Polymers” John Wi Iey
& 8ons* Inc+New Yoridj60
)) o, = Weight fraction of component 1 08: Weight fraction of component 2 Oi: Weight fraction of component - 7 g, : Glass transition point of component 1 homopolymer K)・
Glass transition temperature ('K) Tgi of biaxial component 2 homopolymer
: Glass transition point ('K) of component i homopolymer Tg : Glass transition point ('K) of copolymer of component 1.2,...i where Or + 0 +...=LO, -1.

=1 Depending on the composition of the polymer, a crosslinking reaction may occur, but it is generally calculated assuming that no crosslinking reaction occurs.

The Tg point of a homopolymer of typical external monomers is as follows.

<Homopolymer><Tgpoint> Polymethyl acrylate 8°C polymethyl methacrylate 105°C polyethyl acrylate -23
°C Poly n-butyl acrylate -54 °C 4 °C Polymybutyl acrylate -24 °C Poly 2-ethylhexyl acrylate -85 °C Polyacrylic acid
106℃ polymethacrylic acid 14
4℃ polystyrene 100℃ polyvinyl acetate 30℃ polyacrylonitrile 96℃ polyhydroxyethyl acrylate -31℃ polyhydroxyethyl methacrylate
55°C polyacrylamide 165°C [Production method of acrylic polymer] Acrylic polymer company with a weight average molecular weight of 200,000 or more in the present invention, 0.1 to 100 parts by weight of monomer
Using around 1.5 parts by weight of catalysts (azobisisobutyronitrile, azobiscyclohexanecarbonitrile, benzoyl peroxide, ammonium persulfate, etc.), bulk polymerization method, solution polymerization method, emulsion polymerization method, suspension polymerization method Such,
It can be synthesized by conventional polymerization methods.

In the case of solution polymerization, a solvent that does not exhibit large 2IJII migration, such as ethyl acetate, acetone, n-hexane, or toluene, is used.

Moreover, the weight average molecular weight in the present invention is 500 to 30,0
The 00 acrylic polymer can be produced by bulk polymerization method, solution polymerization method,
Polymerization can be carried out by emulsion polymerization or the like, using any of the following means or a combination of two or more of them.

(1) Increase the amount of catalyst to about 3 to 8 parts by weight based on 100 parts by weight of monomer.

(2) Polymerization is carried out in a solvent with large chain transfer such as isopropyl alcohol.

In addition, when performing isocyanate crosslinking or melamine crosslinking on the resulting polymer, the hydroxyl group of isopropyl alcohol interferes with lame crosslinking, so it is recommended to replace most of the isopropyl alcohol with a solvent such as ethyl acetate or toluene after polymerization. preferable.

(3) Thioglycerol (3-mercapto-1,2-propanediol) [00Ht OH (OH) CHt 8 H1 Ethylene thioglycol (mercaptoethyl alcohol) H80HtOH*OH.

Thioglycolic acid (mercaptoacetic acid) H8C! HzOOOH1 n-dodecyl mercaptan O1*H*sSH.

Polymerization is carried out by adding a chain transfer agent such as Except for the above-mentioned chain transfer agent, dodecyl mercaptan, it can also be a functional group such as incyanate crosslinking or melamine crosslinking.

[Production method of adhesive composition]

The thus obtained acrylic polymer having a weight average molecular weight of 20α000 or more and a weight average molecular weight of 1.500 to 30,0
The resin composition for pressure-sensitive adhesives of the present invention can be obtained by blending with the acrylic polymer of No. etc. can also be added.

In addition, in order to prevent contamination or transfer of adhesive to the protected surface of a plate-shaped object, various types of crosslinking such as protected anate crosslinking or melamine crosslinking, amine crosslinking or acid crosslinking using glycidyl groups, metal crosslinking using carboxyl groups, etc. It is desirable to crosslink the adhesive composition by a method.

[Reference examples, working examples, comparative examples]

Reference examples, working examples, and comparative examples will be shown below to more specifically explain the present invention, but the present invention is not limited thereto. In each example, parts and - indicate parts by weight and % by weight, respectively.

Further, the preparation of the surface protection film, the measurement of adhesive strength, the weatherometer test, and the measurement of pattern workability were carried out by the following methods.

(1) Preparation of surface protection film After diluting the adhesive composition with a 1/1 ethyl acetate/cyclohexane solvent to make a solution with a solid content of 10% by weight, a predetermined amount of a crosslinking agent is added as needed.
This was applied directly onto a 70 micron thick soft polyvinyl chloride film or a 25 micron thick polyester film to a dry thickness of 8 microns, and then heated at 60°C for 2 hours.
Dry for a minute.

After drying, a release paper was pasted on the coated product, and after aging at 60°C for 2 days, it was subjected to the following test.

(2) Measurement of Adhesive Strength The 180 degree peeling strength against the test plate was measured according to the adhesive strength section of xxs z 0237 (Adhesive Tape and Adhesive Sheet Testing Methods).

However, the test plate Fi0.3m thick 8U8304-OF.

After crimping a surface protection film test piece using a 0.8 simple thick aluminum plate JI8H4000/Al100F with a 2B surface finish or alumite processing, the temperature was 23°C and the relative humidity was 6.
5%, and the initial adhesive strength was measured after 30 minutes under no load.

In addition, after bonding the surface protection film test piece, it was left in a dryer at 60°C for 4 or 12 days under no load, and then taken out and
After being placed at 3°C and relative humidity of 65°C for more than 1 hour, changes in adhesive strength were measured.

When measuring the initial and oral change adhesive strength, contamination and adhesive transfer to the test plate were also observed.

(3) Weatherometer (trademark, the same applies hereinafter) Test Suga Test Instruments Co., Ltd. Good Weather Resistance Tester Sunshine Super Long Life Weather Meter WBL-8UN-HOH type was used, test plate (0.3 thick 5U83Q4-OF, Tests were conducted for 100 hr or 300 hr with rainwater directly hitting the surface protection film test piece that was crimped onto a 0.8i* thick aluminum plate (JI8H4000/Al100P) with a 2B surface finish or alumite finish.

Temperature: 40°C, 1 cycle: 50 minutes, including rainfall of 10 minutes, 100 hr, or 300 hr, sampling, 23°C,
After being placed at a relative temperature of 65 degrees for more than 1 hour, JIS Z
180 to the test plate according to the adhesive force section of 0237.
The adhesive strength was measured after peeling off the sample, and contamination and adhesive transfer to the test plate were observed.

(4) Measurement of scratch workability After pressing a surface protection film test piece onto a test plate (0.3 adjustment thickness 8US304-CP, surface 2B finish) at 23℃ and relative humidity 65℃ for 1 day, the following In this way, a deep drawing test was conducted. Using the ERIOH8EN universal metal thin plate deep pattern tester 142-12, press a test piece with a diameter of 90 mm, so that the test piece is inside the ridge, and then press the test piece with a diameter of 50 mm. , Shoulder 7. Deep draw with a 5 m R embossed punch so that the actual emboss depth is 81 m or 18 ropes.

Reference Example 1 30 parts of 100 parts of a monomer mixture consisting of 47 parts of n-butyl acrylate, 47 parts of 2-ethylhexyl acrylate, and 6 parts of 2-hydroxyethyl acrylate and 70 parts of ethyl acetate were mixed with a stirrer, a thermometer, The reaction was started by adding 0.2 parts of azobiscyclohexanecarbonitrile to a four-loop flask equipped with a nitrogen gas blowing device, a dropping funnel, and a reflux condenser, and raising the temperature to 80°C while stirring in a stream of nitrogen gas. The remaining 970% of the monomer mixture
A mixture of 30 parts of ethyl acetate and 30 parts of ethyl acetate was continuously added dropwise over 2 hours to react, and after the addition was completed, 50 parts of ethyl acetate was added and stirring was continued for 5 hours at the same temperature until the solid content was 38 parts. A polymer solution with an equivalent weight of 16.711 was obtained.

Let us explain about the L equivalent. Coronate L is an isocyanate-based crosslinking agent manufactured by Nippon Polyurethane Industry Co., Ltd., and the Coronate L equivalent is the amount of functional groups in the polymer expressed as the amount of Coronate L that reacts with it. . Specifically, the total amount of functional groups capable of reacting with isocyanate groups in the polymer solid content 100.9 is sufficient to react with the visible amount (7
) was calculated using the following calculation.

Polymer 100.9 x 42 Amount of functional group-containing monomer C) Coronate L equivalent = □ Here, the "functional group" of the functional group-containing monomer is a carboxyl group or a human = refers to xy group. "42" in the numerator is N0
The molecular weight of O (incyanate group), rO, 13J, refers to the content of Neo in Coronate L form, 13%. The glass transition point of the polymer obtained in Reference Example 1 was calculated using the above formula to be -69°C, and the weight average molecular weight of the polymer was measured using the above method and was 2,190.000.

Reference Example 2 Monomer mixture is n-butyl acrylate) 49.5 parts, 2
-Solid content: 39.4%, Coronet) L equivalent: 2
．． A 78F polymer solution was obtained.

The glass transition point of the polymer was calculated using the above formula to be -70°C, and the weight average molecular weight of the polymer was measured using the above method to be 250,000 h-p.

Reference example 3 Stirrer, thermometer, nitrogen gas blowing device, dropping funnel,
and a four-loaf flask equipped with a reflux condenser.
and 8 parts to polyacrylic acid alone A-10 manufactured by Toagosei Kagaku Kogyo Co., Ltd., and heated to 75° C. with stirring in a nitrogen stream. A homogeneous solution of 1 part of azobisisobutyronitrile in 100 parts of a monomer mixture consisting of 85 parts of n-butyl acrylate, 12 parts of acrylonitrile, and 3 parts of acrylic acid was charged therein with vigorous stirring. The reaction was carried out at 75° C. for 6 hours to obtain an aqueous dispersion of the polymer. The dispersion is cooled, the polymer particles in the dispersion are thoroughly washed with water, and finally the water is drained.

Next, put toluene into the flask so that the solid content is 3 (l) and raise the temperature to about 80°C to dissolve the polymer particles.Finally, dehydration distillation is performed at normal pressure, and the water-toluene mixture is The boiling water is distilled off and dehydrated.When the temperature suddenly rises to 100℃ or higher, the solid content is 30.2 cm and the Coronate L equivalent is 13.5 when the dehydration is completed.
A toluene solution of polymer No. 11 was obtained.

The glass transition point of the polymer was calculated using the above formula and was found to be -40 DEG C., and the weight average molecular weight of the polymer was measured using the above method and was found to be 520.000.

Reference Example 4 Monomer mixture is n-butyl acrylate) 49.5 parts-1
2-ethylhexyl acrylate) 49.5 parts, and 2
The same procedure was used as in Reference Example 1, except that 1 part of hydroxyethyl acrylate was used, and 0.6 part of azobiscyclohexane carbonitrile was used. A combined solution was obtained.

The glass transition point of the polymer was calculated using the above formula to be -70°C, and the weight average molecular weight of the polymer was measured using the above method and was found to be 165,000.

Reference Example 5 20 parts of n-butyl acrylate, 0.2 parts of ethylene thioglycol (mercaftethyl alcohol), and 90 parts of toluene were placed in a four-stage system equipped with a stirrer, a thermometer, a nitrogen gas blower, a dropping funnel, and a reflux condenser. The reaction was started by adding 0.4 parts of azobisisobutyronitrile to 75°C while stirring in a nitrogen stream. A mixture of 0.8 parts of alcohol-y), 10 parts of toluene, and 0.6 parts of azobisisobutyronitrile was reacted while being continuously added dropwise over 3 hours. Add 0.1 part of ronitrile and raise the temperature to 80°C and continue stirring for 3 hours. The weight average molecular weight of the polymer was measured using the method described above and was found to be 21.000.

Reference example 6 Stirrer, thermometer, drilling gas blower, dropping funnel,
Then, 233 m of isopropyl alcohol was placed in a four-hole flask equipped with a reflux condenser, and the temperature was raised to 80°C while stirring in a stream of hydrogen gas.

100 parts of a monomer mixture consisting of 65 parts of n-butyl acrylate, 30 parts of 2-ethylhexyl acrylate, and 5 parts of methacrylic acid were uniformly mixed with 5 parts of azobisisobutyronitrile. The reaction was carried out by continuous dropwise addition over a period of time, and after the completion of the dropwise addition, stirring was continued for 3 hours at the same temperature to obtain a polymer isopropyl alcohol solution with a solid content of about 30%. This polymer isopropyl alcohol solution was concentrated under reduced pressure at 70°C and -600 swHg to a solid content of about 90%. Furthermore, toluene was added and solid concentration was continued, solid content 90.2%, coronet) L equivalent 18.8N
A toluene solution of the polymer was obtained. The glass transition point of the polymer was calculated using the above formula and was -59°C, and the weight average molecular weight of the polymer was measured using the above method and was 3.09.
It was 0.

Reference Example 7 A monomer mixture containing 65 parts of n-butyl acrylate and 2 parts of n-butyl acrylate
A polymer toluene solution with a solid content of 89.3% was obtained in the same manner as in Reference Example 6, except that -ethylhexyl acrylate was used in an amount of 35 parts. This polymer does not contain any functional group that crosslinks with Coronae) L or the like. The glass transition point of the polymer was calculated using the above formula and was found to be -66°C, and the weight average molecular weight of the polymer was measured using the above method and was found to be 1,860.

Reference Example 8 2 parts of toluene instead of 233 parts of inpropyl alcohol
Reference Example 6 except that the volume was 33 parts and vacuum concentration was performed only once.
Similarly, solids content 89.8%, coronet) L equivalent is
, sy polymer toluene solution was obtained. When the glass transition point of the polymer was calculated using the above formula, it was -59°C, and when the weight average molecular weight of the polymer was measured using the above method, it was 3.
It was 6.000.

Reference Example 9 First, 15 parts of n-butyl acrylate were placed in four flasks, and 3 parts of ethylene thioglycobemercaptoethyl alcohol were added dropwise continuously over 3 hours.
-Solid content: 49.5%, Coronet) in the same manner as in Reference Example 5, except that the butyl acrylate was changed to 70 parts and the ethylene thioglycol (mercaptoethyl alcohol) was changed to 12 parts.
A polymer solution with an L equivalent of 62.11 was obtained. The glass transition point of the polymer was -54°C, and the weight average molecular weight of the polymer was determined to be 1,270 by the method described above.

Examples 1 to 9, Comparative Examples 1 to 15 80% by weight of the high molecular weight acrylic polymers obtained from Reference Examples 1 to 4 and the low molecular weight acrylic polymers obtained from Reference Examples 5 to 9. Table 1 shows the 20% by weight of the solid content of the coalesce.
After mixing as shown in Table 1, a surface protection film was prepared using the method described above. However, as a crosslinking agent, 172 equivalents of Coronate L was added as shown in Table 1, and the crosslinking agent was added directly to a 70 micron thick soft polyvinyl chloride film. Coated.

Table 1 shows the results of adhesion measurement, weatherometer test, and pattern workability measurement using the surface protection film according to the methods described above. The test plate was 8U with a thickness of 0.3%.
8304-OF, surface 2B finish was used. A comparative example in which a low molecular weight acrylic polymer was not mixed was also shown.

In Table 1, the X marks in the adhesive strength and weatherometer test items are test plates (808304-01 with o and am thickness).
1 surface 2B finish) where contamination or adhesive transfer is observed. Items without an X mark indicate cases where neither contamination nor adhesive transfer was observed. Items in parentheses indicate the initial adhesive strength of 1 It shows the multiple of adhesive force when . Also, in the item of pattern processing property, the x mark indicates that the surface protection film was tested on a test plate (0.3% thick 8U8304-op, surface 2B) in the deep drawing cup test.
The mark Δ indicates that the surface protective film has peeled off from the test plate (finishing) and has lifted up severely, and the mark Q indicates that the surface protective film has not peeled off or lifted off the test plate. (The above symbols are the same as in Tables 2 and 3) Examples 10 to 15, Comparative Examples 16 to 21 High molecular weight acrylic polymer obtained from Reference Example 1 or 2 and from Reference Example 5t or 6 After mixing with the obtained low molecular weight acrylic polymer in various ratios shown in Table 2, a surface protection film was produced by the method described above. However, as a crosslinking agent, 1/3 of the equivalent amount of Coronet) L was added as shown in Table 2, and the mixture was directly coated onto a 70 micron thick flexible polyvinyl chloride film. The surface protection film was used to measure adhesion, weather meter test, and pattern staining using the methods described above.
The results of the workability measurements are shown in Table 2. In addition,
The test plate is 1908304-OF with a thickness of 0.3 mm, surface 2B.
Finishing was used. A comparative example in which a low molecular weight acrylic polymer was not mixed was also shown.

Examples 16-21, Comparative Examples 22-27 Polystyrene equivalent weight average molecular weight obtained from Reference Example 3 52
0.000 acrylic polymer solid content equivalent to 75% by weight
and 25% by weight in terms of solid content of the acrylic polymer having a polystyrene equivalent weight average molecular weight of 3.090 obtained from Reference Example 6.
After mixing, a surface protection film was produced by the method described above. However, the crosslinking agent was Coronate L or an n-butylated melamine crosslinking agent manufactured by Mitsui Toatsu Chemical Co., Ltd., trade name Kneepan 22B, added in various amounts as shown in Table 3, and applied directly to a 25 micron thick polyester film. did. Table 3 shows the results of adhesion measurement and weatherometer test using the surface protection film according to the method described above. However, the test plate used was an alumite-processed 0.8 m thick aluminum plate JI8H4000-A1100F.

A comparative example in which an acrylic polymer having a polystyrene equivalent weight average molecular weight of 3.090 was not mixed was also shown.

Example 22.23 Comparative Examples 28-30 Polystyrene equivalent weight average molecular weight obtained from Reference Example 3 52
After mixing the acrylic polymer having a weight average molecular weight of 0.000 and the acrylic polymer having a polystyrene equivalent weight average molecular weight of 1860 obtained from Reference Example 7 at various ratios shown in Table 4, a surface protection film was prepared by the method described above. did. However, no crosslinking agent was used, and the coating was applied directly to a 70 micron thick flexible polyvinyl chloride film.

Table 4 shows the results of adhesion measurement, quesaometer test, and scratchability measurement using the surface retention film using the methods described above. In addition, the test plate was 0.3 mm thick.
USAO4-OP, surface 2B finish was used. A comparative example in which a low molecular weight acrylic polymer was not mixed was also shown.

(Effect of the invention) The resin composition for adhesives of the present invention can be used as it is or by adding a crosslinking agent etc. as an adhesive composition, especially as an adhesive for surface purulent film, and can be used as a cough adhesive composition. The product shows little change in adhesive strength over time during the period of application, has excellent weather resistance and peeling workability, does not cause contamination or migration of adhesive to the protected surface after peeling off, and is It has a moderate adhesive strength, and is an excellent product that will not peel off from the metal plate during processing even if it is applied to a metal plate and used for processing such as stamping, bending, punching, etc. It is.

Claims (1)

[Claims] 1. 60 to 95% by weight of an acrylic polymer with a weight average molecular weight of 200,000 or more and a weight average molecular weight of 1,50
A resin composition for an adhesive comprising 5 to 40% by weight of an acrylic polymer of 0 to 30,000%.