JPS6016479B2 - Surface protection material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure-sensitive surface protection material for the purpose of protecting the surface of an article.

Various metal plates such as stainless steel plates, steel plates, and aluminum plates, synthetic resin plates such as acrylic, vinyl chloride, and polyester plates, and glass plates may have scratches or scratches on their surfaces due to collisions with pond materials or friction during transportation and handling. Particularly in the case of decorative boards, the surface loses its luster or spots are formed due to contamination by tentacles, etc., and the quality often deteriorates significantly.

In order to temporarily protect items from damage during transportation, discoloration, and fading due to gas, etc., pressure-sensitive adhesive and/or adhesive processing is applied to base materials made of plastic films, sheets, tapes, and various types of paper. has been generally used as a surface protection material. The adhesive compositions used in conventional pressure-sensitive surface protection materials are as follows:
Most are solvent-based, which are mainly made of natural rubber, and emulsion-based, where natural rubber latex alone is used, but both have the problem of reduced performance due to deterioration. In general, it is important that the pressure-sensitive surface protection material has very good cohesive strength and adhesive strength of 20 to 200 m/m/s. However, in the case of natural rubber, it is very difficult to have excellent cohesive force and appropriate adhesion strength, and in particular, the adhesive strength for polar objects is 200 mm or more, and on the contrary, it is difficult to achieve adhesive strength for non-polar objects. It is often less than 20 yen/1 yang width. Also, the film resistance is poor, for example, 1 at 30qo.
After a week, the adhesion strength to stainless steel plates, glass plates, etc. reached about twice that before the test, and there were drawbacks such as a portion of the adhesive remaining on the adherend after peeling off. Furthermore, in the case of styrene-ptadiene copolymer, which is a typical synthetic rubber, its adhesive strength is particularly low to non-gutter materials, and its weather resistance is also poor. 0
It often comes close to peeling off from objects. Furthermore, in the case of acrylic polymers, which are generally said to have excellent weather resistance, their adhesive strength to non-polar substances is low, and their adhesive strength to polar substances increases over time, making it difficult to remove them. There are drawbacks such as.
The present inventors have provided an improved pressure-sensitive surface-protecting material by eliminating the drawbacks of the conventional pressure-sensitive surface-protecting materials. 10% by weight, isoprene or a mixture of isoprene and other conjugated genes (however, the ratio of isoprene in the conjugated genes is 3
weight% or more) 39.9 to 99. The gel content is 40 to 6% by weight, and 0 to 6% by weight of other polymeric components.
By applying and drying an adhesive composition consisting of an aqueous dispersion containing 95% by weight of isoprene polymer as the sole or main rubber component, weather resistance is significantly improved compared to conventional products. Therefore, it is possible to obtain a pressure-sensitive surface protective material that is easy to peel off after adhering to the utensils, and does not leave any adhesive or stains on the utensils.

To explain in more detail the structure and significance of the above-mentioned specific isoprene-based polymer used in the present invention, firstly,
It is necessary to have an appropriate amount of carboxyl group in the polymer, and this carboxyl group is introduced into the polymer by an unsaturated carboxylic acid, and the amount is 0.1 to 1 as the unsaturated carboxylic acid. It is necessary to set the amount within a range of % by weight.

When the amount of unsaturated carboxylic acid exceeds 1% by weight, the adhesive strength increases, but disadvantages such as the polymer itself becoming hard occur. Further, if the unsaturated carboxylic acid content is less than 0.1% by weight, disadvantages such as poor adhesion, particularly to non-polar substances, occur. The amount of unsaturated carboxylic acid preferably ranges from 0.5 to 5% by weight. As unsaturated carboxylic acids, monobasic acids such as acrylic acid, methacrylic acid, and maleic acid monoalkyl esters, which can be copolymerized with conjugated diene such as isoprene, and dibasic acids such as maleic acid, fumaric acid, and itaconic acid are used. can be done. The second condition that the isoprene polymer used in the present invention should have is:
The content of the conjugated gene component in the polymer is 39.9% by weight or more and 99.9% by weight or more. The groove weight percent or less, preferably 60 to 9 weight percent, and at least 3 weight percent or more of the conjugated gene component is isoprene. Conjugated gene content is 3
9. When the amount is less than % by weight, the adhesive layer obtained from the aqueous dispersion loses its tackiness, and the adhesive strength to various adherends becomes 20 yen/10 yanagi width or less. If the content of conjugated diene is more than 99.9% by weight, the adhesion to various utensils will be reduced and the durability will be poor. In addition to isoprene, conjugated gene components include ptadiene, chloroprene,
It may contain 213-dimethylbutadiene or two of these, but if it does not contain isoprene, the adhesive layer loses its tackiness and becomes difficult to adhere to objects. When isoprene is included in the conjugated gene component, the adhesive layer has appropriate tack and adhesion and excellent cohesive strength, and at the same time retains its initial performance over a long period of time. It appears when the ratio is 3% by weight or more. The third condition that the isoprene polymer used in the present invention must have is that the polymer contains 40 to 95% by weight of gel.

If the gel content is less than 4% by weight, the adhesion to the object will be too strong and the cohesive force will be insufficient, leaving adhesive on the object when removed. Moreover, when the gel content is more than 95% by weight, the adhesiveness is almost eliminated and the adhesive strength to objects becomes close to zero. In addition, in the present invention, the gel content refers to 1 ml of isoprene polymer in 200 cc of toluene.
After heating at 3,000 ℃ for 24 hours, the polymer was placed in a furnace using a glass filter (No. 3), and the furnace-separated polymer was dried and weighed.

The ratio of the weight of the swollen gel to the weight after drying of the polymer separated during gel content measurement is generally referred to as the swelling degree of the gel, and this indicates the properties of the gel. Although to a lesser extent, it does affect the performance of the resulting surface protection material; if the swelling degree of the gel is too small, the tackiness will decrease, and if the swelling degree of the gel is too large, the cohesive force will decrease. The degree is preferably in the range of 5-25. The optimal range of gel content and swelling degree of the gel changes depending on the unsaturated carboxylic acid content of the isoprene-based polymer.
The unsaturated carboxylic acid is 0.1 to 1. When the weight percent of the gel is 85 to 95 weight percent, the swelling degree of the gel is 5 to 15, and the unsaturated carboxylic acid is 1.0 to 5. % by weight, the gel content is 70-85% by weight, the gel swelling degree is 10-20, and the unsaturated carboxylic acid is 5.0-10.0% by weight, the gel content is 40-7% by weight. If the swelling degree of the gel is in the range of 15 to 25% by weight, the pressure-sensitive adhesive layer of the resulting pressure-sensitive surface protection material best satisfies the required performance of tack and adhesive strength. The isoprene polymer used in the present invention may optionally contain other polymerization components (referred to as monomer components for convenience) in addition to the above-mentioned unsaturated carboxylic acid and conjugated diene monomer.

The introduction of this third monomer component is effective when consideration is given to compatibility when blending the aqueous dispersion of the isoprene polymer with other substances. However, the amount of the third monomer component should be kept within a range of not more than 5% by weight in the isoprene-based polymer, and if the content of the third monomer component exceeds 5% by weight, the amount of the isoprene-based polymer Adhesiveness decreases markedly, and depending on the type of utensil, it may not stick to the surface.
When the first monomer component used is such that the glass transition temperature of the polymer consisting only of the third monomer component exceeds about 80 qo, the amount of the third monomer component is preferably 35% by weight. I'll keep it below. Examples of the third monomer component include styrene, substituted styrene, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate,
Examples include 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and (meth)acrylonitrile. The adhesive composition used in the present invention containing the specific isoprene polymer as described above is an aqueous dispersion containing the isoprene polymer as the only rubber component (
(hereinafter referred to as isoprene-based latex), and the isoprene-based latex also contains other rubber components mixed in the form of an aqueous dispersion or other suitable form. I can do it.

The above-mentioned isoprene-based latex is obtained by dissolving (or partially swelling) an isoprene-based polymer previously produced by a method other than the emulsion polymerization method in a solvent, then emulsifying it in water in the presence of an emulsifier, etc., and removing the solvent. It is also possible to use products prepared by dispersing isoprene-based polymers in water using a similar method. Those prepared by emulsion polymerization using a radical polymerization initiator and optionally removing residual monomers from the system are better.
Differences in particle size or distribution give preferable results. The concentration of the isoprene polymer in the isoprene latex is not particularly limited, but a range of 30 to 6% by weight is usually suitable.

The viscosity of the isoprene latex is not particularly limited, but is preferably in the range of 10 ps to 300 ps. Although the particle size of the isoprene polymer is not particularly limited, a range of 0.05 to 1.0 mm is usually suitable. When it is desired to increase the viscosity of the latex, add a water-dropping polymer such as methylcellulose, carboxylated methylcellulose, or polyvinyl alcohol to 1000 parts by weight (hereinafter abbreviated as parts) of the solid content in the isoprene-based latex. 0.1-3. It is possible to add more counties. The emulsifier that can be contained in the isoprene latex is a nonionic and/or anionic emulsifier, and one or more of these can be used. As a nonionic emulsifier, the degree of polymerization of the polyoxyethylene part is 5 to 5.
There are 20 polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan alkyl esters, etc., and anionic emulsifiers include fatty acids. Salts, alkylaryl sulfonates, higher alcohol sulfate esters, alkyl sulfosuccinic acids, and the like can be used. The anti-aging agent may be added to the adhesive composition used in the present invention in the form of an emulsion or other form.

Further, oxides or hydroxides of divalent or trivalent metals such as zinc oxide, magnesium oxide, calcium oxide, or other salts may be included for the purpose of improving cohesive force. In addition to the above-mentioned isoprene-based polymer, the pressure-sensitive adhesive composition used in the present invention may contain other elastic bodies in an amount not exceeding 7 parts per 10 parts of the isoprene-based polymer. Examples include polyisobutene, chloroprene, styrene-butadiene copolymers, natural rubber, etc., and these are usually preferably mixed with the isoprene latex in the form of an aqueous dispersion.

Further, the adhesive composition used in the present invention may contain a resin in an amount not exceeding 5 parts per 10 parts of the above-mentioned isoprene polymer. Resins include hurias, melamines, phenolics, epoxies, rosins, polyterbenes, and aromatic petroleum resins, which are usually combined with isoprene latexes or other elastomers in the form of aqueous emulsions. Mixed into latex. The pressure-sensitive surface protection material of the present invention can be obtained by applying and drying the pressure-sensitive adhesive composition as described above on a base material.

The material used here may be any of various synthetic resin sheets, films, tapes, etc., and various papers such as kraft paper, Japanese paper, parchment paper, wood-free paper, medium-quality paper, and rough paper. If necessary, the base material may be subjected to a primer treatment, a peeling treatment, etc. prior to applying the adhesive composition to the base material. There is no particular restriction on the amount of the adhesive composition to be applied, but the appropriate solid content is usually about 5 to 100 coats per coat. The pressure-sensitive surface protection material of the present invention can be used for a very wide range of objects, regardless of whether it is non-polar or polar.In particular, for objects with oil stains, it can be used to protect the objects and at the same time remove the oil stains. It is very effective in removing such things.

The present invention will be further explained below with reference to Examples. Parts in the examples mean parts by weight.

Example 1 8 parts of isoprene, 1 part of methacrylic acid and 1 $ part of methyl methacrylate are emulsified in 15 parts of water in the presence of 7 parts of polyoxyethylene nonyl phenyl ether sulfate,
After replacing the inside of the system with nitrogen, the temperature was raised to 70°C.

Then, 0.25% of potassium persulfate was substituted with nitrogen in advance.
of the aqueous solution was added to the system to start polymerization. Polymerization was carried out for 2 calm hours, and when the polymerization rate reached 99%, it was cooled to room temperature. The resulting aqueous dispersion had a viscosity of 130 ps, a solid content of 45%, and a particle size (as measured by an electron microscope after fixation with osmic acid) of about 0.1 French. A portion of this aqueous dispersion was added to methanol containing an antiaging agent, and the coagulated polymer was thoroughly washed with water and then dried at room temperature under reduced pressure. Using a part of the polymer, the gel content is determined using toluene as a solvent.
When the degree of swelling of the gel was measured, it was found that the degree of swelling was %% and 1%, respectively.
It was 5. To this isoprene-based latex, a 5% aqueous solution of methylcellulose (Kiyoshi Hanoi, Japan) was added as a thickener at a ratio of 0.5 part per 100 parts of solid content in the latex, and the adhesive for surface protection materials was added. It was made into a drug composition. The above composition was applied to the untreated side of the base material (kraft paper with a thickness of 20 mm) to a thickness of 15 mm, and heat-treated for 5 minutes in a hot air dryer at 12 mm to 0.0 mm to obtain a surface protective material. It was created.

After the heat treatment, the pieces were allowed to cool to room temperature for about 1 hour, and the tact and weather resistance were measured using the ball rolling method. Here, the above-mentioned ball rolling method is to attach an adhesive tape of 1 length to a slope with a 30-degree angle in a range of 10 to 2 ratios from the apex, and to make the tape 1/32 inch in diameter from the apex. In this method, a steel ball with a size of 32 pupils from 1 inch to 1 inch is rolled, and the degree of tack is expressed by the size of the largest ball that stops on the adhesive tape. Regarding weather resistance, an adhesive tape-shaped test piece with a thickness of about 2
Paste it on soft glass, set it in a fade meter so that the glass plate is perpendicular to the light source, and let it deteriorate for a specified period of time in such a way that the light shines on the adhesive through the glass plate. We investigated the adhesion when the test piece was removed, whether the adhesive composition remained on the glass after the test piece was removed, and whether cloudiness remained on the glass.
The viscosity of the adhesive composition for pressure-sensitive surface protection material is 250 ratio p.
S, tack is 2, 180 degree peeling force is 80 degrees/10 rib width,
Regarding weather resistance, no particular change in performance was observed within 20 q hours, and even after peeling off, not only zero adhesive but also no clouding remained on the glass plate. In addition, no particular change was observed in the heat resistance at 80 qo within 10 hours in the pressure-sensitive surface protective material. Example 2 The same isoprene-based latex 8 as in Example 1 was used for the foundation.
Blend natural rubber latex 2 Bodu and add 0.0% 5% aqueous solution of methyl cellulose to this. In addition to same-day R, it was used as an adhesive for pressure-sensitive surface protection materials.

The viscosity of the composition at this time was 270 ps, and using this, a pressure-sensitive surface protection material was prepared by a conventional method, and various properties were examined. The tack of the non-E-sensitive surface protection material is 2. The 180 degree peel strength is 70 mm/1 inch width, the weather resistance is unchanged within 20 hours, and the retention rate of 180 degree peel strength is 100 degrees. It shows an excellent performance of ~120%, and its heat resistance does not change significantly within 10 years.
The retention rate of 180 degree peel strength was 100 to 110%, and no adhesive was left behind after peeling off from various adherends, demonstrating excellent performance. The above retention rate is (180 degree peel strength of the test piece taken out during the weather resistance test) x
It is a value calculated by 100/(180 degree peel strength of the test piece before film resistance test 0). Example 3 In place of the mo/mer of Example 1, 2 parts of acrylic acid, 8 parts of isoprene and 1 part of styrene were used, and 2 parts of polyoxyethylene nonyl phenyl ether sulfate and dodecylbenzene sulfone were used as emulsifiers. Using 3 parts of acid soda and 110 parts of water, the monomer mixture was divided into 3 portions and 5
Polymerization was carried out in the same manner as in Example 1, except that it was added to the system every hour.

After 2 hours of cooling, the polymerization rate reached 99%.

When analyzed in the same manner as in Example 1, the amount of gel was 92%.
, the swelling degree of the gel was 7. The pressure-sensitive surface protection material prepared in the same manner as in Example 1 had a tack of 2 and a 180 degree peel strength of 150 degrees/1 cross width, and no change in weather resistance was observed in the tack or 180 degree peel strength within 20 q hours. 80 again
As for the heat resistance of 00, there was no change in tack and 180 degree peel strength, and even after peeling off, no adhesive remained on various adherends, and no stains were caused. Examples 4 to 10 In the same manner as in Example 1 or Example 3, an isobrene latex was polymerized, and a composition for a pressure-sensitive surface protection material was prepared using this latex as a main component.

The composition and properties of these isoprene-based polymers and the various performances of the pressure-sensitive surface protection materials are summarized in Table 1.

In addition, those outside the scope of the present invention are also shown as comparative examples. Kosanko As is clear from Table 1, the gel shed amount is within the range specified by the present invention. These are essential conditions for the pressure-sensitive surface protection material to exhibit its various properties.

Claims (1)

[Claims] 1 Unsaturated carboxylic acid 0.1 to 10% by weight, isoprene or a mixture of isoprene and other conjugated diene (however, the ratio of isoprene in the conjugated diene is 30% by weight or more)3
9.9-99.9% by weight and other polymeric components 0-6
A pressure-sensitive adhesive composition consisting of an aqueous dispersion containing an isoprene polymer having a gel content of 40 to 95% by weight as the sole or main rubber component is applied to a base material and dried. Surface protection material.