JP3133258B2 - Release treatment agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a releasable treating agent, and more particularly, to a product such as a pressure-sensitive adhesive tape, a pressure-sensitive adhesive sheet, a pressure-sensitive adhesive sheet, and a tape or the like which is in contact with and overlaps the pressure-sensitive adhesive surface. The present invention relates to a release treatment agent that makes the back surface or the release paper surface peelable.

[0002]

2. Description of the Related Art Conventionally, release agents used for the above purposes are roughly classified into silicone-based release agents and non-silicone-based release agents. Among them, the silicone-based release treatment agent has excellent release performance for both rubber-based and acrylic-based pressure-sensitive adhesives.

However, in order to form a release layer with these release treatment agents, heat treatment at a high temperature is necessary, so that it cannot be used for a support having poor heat resistance such as OPP and polyethylene. However, there is a problem with the silicone low molecular weight substance remaining in the silicone-based release treatment agent and a drawback in writing properties.

On the other hand, non-silicone release agents include long-chain acrylate polymers, fluorinated alkylvinyl monomer polymers, and polyvinyl alcohol (hereinafter simply referred to as PVA).
) And carbamates, but these release agents are not satisfactory in terms of release properties and residual adhesiveness.

[0005] Also, Japanese Patent Publication No. 29-2989 discloses P
A strippable treating agent comprising a reaction product obtained by reacting VA with stearyl isocyanate is described. This PVA
The most widely used non-silicone-based release agents are those that exhibit a release effect with an extremely small amount of coating, have excellent performance during high-speed release, and have good writing and heat resistance. ing.

However, this type of release treating agent has poor adhesion to the support and flexibility of the formed release layer. In addition, the above-mentioned releasable treating agent has poor solubility in a solvent, and there is a problem in workability such as gelling of the solution or precipitation or precipitation of the releasable treating agent component in winter or the like.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a releasable treating agent which is excellent in adhesion and flexibility to a support and which is excellent in workability by improving solubility in a solvent. is there.

[0008]

The above object is achieved by the present invention described below. That is, the present invention is a releasable treating agent comprising a reaction product of a PVA-based copolymer onto which an aliphatic polyester is grafted and a saturated fatty acid having 12 or more carbon atoms.

The present inventors have conducted intensive studies to solve the above problems, and as a result, the PVA was modified by grafting an aliphatic polyester to the PVA, and the adhesion, flexibility and solubility were improved. When a reaction product obtained by reacting a saturated fatty acid having 12 or more carbon atoms with the graft copolymer is used as a releasable treating agent, remarkably improved releasability is obtained, and a conventional PVA is used. Has excellent adhesion to a support and flexibility as well as improved solubility in a solvent, as compared with a release treating agent obtained by directly reacting an isocyanate having an aliphatic group having 12 or more carbon atoms with the release agent. It has been found that a sexual treatment agent can be obtained.

[0010] In the release treatment agent of the present invention, PV
When A having a degree of saponification of 60 mol% or more is used as A, and when a ring-opened polymer of polycaprolactone or polyvalerolactone is used as the aliphatic polyester, the above-mentioned excellent performance can be obtained.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to embodiments. The reaction product of the aliphatic polyester-grafted PVA-based copolymer and the saturated fatty acid having 12 or more carbon atoms, which constitutes the release treatment agent of the present invention, is obtained as follows.

First, a PVA-based copolymer is obtained by ring-opening grafting of a lactone compound capable of forming a polyester by lactone ring-opening polymerization, such as an ε-caprolactone compound or a δ-valerolactone compound, as an aliphatic polyester compound on PVA. It is obtained by copolymerization. The PVA used in the present invention has a degree of saponification of vinyl acetate units of 60.
It is a PVA having a weight-average degree of polymerization of 20 to 20,000, preferably 200 to 3,000, by mole% or more.

In the present invention, the caprolactone compound to be reacted with PVA includes various compounds such as ε-caprolactone, monomethyl-ε-caprolactone, monoethyl-ε-caprolactone, monopropyl-ε-caprolactone, and monododecyl-ε-caprolactone. Monoalkyl-ε-caprolactones or dialkyl-ε-caprolactones or ε of a lactone ring in which both of the two alkyl groups are not bonded to the carbon atom at the ε-position but are each substituted on a similar separate carbon atom -The carbon atom at the position is di-
Unsubstituted trialkyl-ε-, in which two or three other carbon atoms are replaced by three alkyl groups
Alkoxy-ε-caprolactones such as caprolactone and ethoxy-ε-caprolactone or cycloalkyl-ε-caprolactone such as cyclohexyl, phenyl- and benzyl-ε-caprolactone, aryl-ε-caprolactone and aralkyl-ε-caprolactone, etc. Is mentioned.

As the δ-valerolactone compound preferably used in the present invention, 5-valerolactone, 3
-Methyl-5-valerolactone, 3,3, -dimethyl-
5-valerolactone, 2-methyl-5-valerolactone, 3-ethyl-5-valerolactone, and the like.

The reaction between PVA and the lactone compound is as follows:
It is carried out by mixing the two and reacting them at a temperature of 10 to 220 ° C. for several hours to several tens of hours, preferably using a suitable catalyst under a nitrogen stream, to obtain a PVA-based copolymer obtained by grafting an aliphatic polyester onto PVA. Coalescence is obtained. In the grafting reaction, the molecular weight of the aliphatic polyester to be grafted onto the PVA, that is, the weight ratio between the PVA and the aliphatic polyester used in the reaction is changed, so that the PVA is changed.
With each characteristic of polyester and aliphatic polyester
An A-based copolymer is obtained.

The weight ratio of PVA to the aliphatic polyester in the above copolymer is preferably in the range of 90 to 60 parts by weight of PVA and 10 to 40 parts by weight of the aliphatic polyester. PVA-based copolymers having more than 90 parts by weight of PVA and less than 10 parts by weight of an aliphatic polyester are superior in performance from PVA, so that the obtained copolymer has good adhesion to a support, The effect of improvement in flexibility and solubility in solvents is small.

On the other hand, a PVA copolymer containing less than 60 parts by weight of PVA and more than 40 parts by weight of aliphatic polyester has a superior performance from aliphatic polyester, and thus has insufficient peelability and the like. It is unsatisfactory as the release treatment agent of the present invention. In the present invention, graft polymerization of a lactone compound onto PVA is performed by mixing the two, preferably adding a catalyst under a nitrogen stream, and stirring at a temperature of 80 to 220 ° C. for several hours. It is also possible to carry out graft polymerization in a molten and heated state using a kneader such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader or a Brabender. The molecular weight of the copolymer thus obtained is about 1 to 500,000, preferably about 1 to 200,000, as a number average molecular weight (in terms of standard polystyrene) measured by GPC. When the molecular weight exceeds the above range, the copolymer has insufficient moldability, while when the molecular weight is less than the above range, the copolymer has insufficient mechanical properties.

Next, the PVA-based copolymer obtained as described above is reacted with a saturated fatty acid having 12 or more carbon atoms to obtain the release treating agent of the present invention. The saturated fatty acid used in the present invention can be represented by the general formula R-COOH. R in the formula is a linear saturated aliphatic group having 11 or more carbon atoms, and includes an alkyl group and an alkenyl group.

Specific examples of these saturated fatty acids having an aliphatic group include lauric acid (R having 1 carbon atom).
1), tridecylic acid (R has 12 carbon atoms), myristic acid (R has 13 carbon atoms), pentadecylic acid (R has 1 carbon atom)
4), palmitic acid (R has 15 carbon atoms), heptadecylic acid (R has 16 carbon atoms), stearic acid (R has 1 carbon atom)
7), nonadecanoic acid (R has 18 carbon atoms), arachiic acid (R has 19 carbon atoms), behenic acid (R has 21 carbon atoms), and lignoceric acid (R has 23 carbon atoms).

Next, the PVA-based copolymer and the carbon number of 1
The reaction with two or more saturated fatty acids will be described. After dissolving or dispersing the copolymer in a molten state or in a solvent, a saturated fatty acid having 12 or more carbon atoms is added, and 60 to 1
The esterification reaction is performed at a temperature of 80 ° C. At this time, water as a by-product is distilled off together with the solvent or under reduced pressure outside the reaction system.

At this time, the reaction ratio of the saturated fatty acid having 12 or more carbon atoms is preferably in the range of 0.2 to 1.1 equivalents to the hydroxyl groups in the PVA-based copolymer. When expressed in terms of weight ratio, it is preferable to use such a ratio that about 50 to 500 parts by weight of a saturated fatty acid reacts and bonds with 100 parts by weight of the PVA-based copolymer. When the amount of fatty acid bound exceeds the above-mentioned equivalent range, it is insufficient in that excess saturated fatty acid remains in the reaction mixture, and on the other hand, when the used amount of saturated fatty acid is less than the above-mentioned equivalent range, it is obtained. The copolymer is insufficient in terms of water repellency and releasability.

After the completion of the esterification reaction, excess saturated fatty acids are removed under reduced pressure. The obtained reaction mixture is poured into a 2 to 5-fold poor solvent such as alcohol to precipitate an esterified product, and the precipitate is separated by filtration and then dried to obtain the desired product of the present invention. The reaction product thus obtained exhibits excellent solubility in solvents such as toluene and xylene, and has excellent properties such as releasability, residual adhesiveness, adhesion to a support, and flexibility. .

In the present invention, as described above, after the aliphatic polyester is graft-polymerized to the PVA, the fatty acid can be easily esterified with the graft copolymer. It was difficult to directly perform an esterification reaction with several 12 or more saturated fatty acids. That is, when PVA is heated to a temperature of 100 ° C. or higher, it gradually undergoes thermal decomposition, and since the softening point of PVA is high, it is difficult to react with fatty acids in a substantially anhydrous or non-plasticized state. Was.

On the other hand, in the present invention, at the time of the initial graft polymerization reaction, when the PVA and the lactone compound are in a mixed state, the white powder PVA and the liquid lactone compound are in an inhomogeneous state. With white powder P
VA changes to a homogeneous reaction product, and despite high temperature, no thermal decomposition of unreacted PVA is observed. In the subsequent reaction with the fatty acid, similarly, PVA (modified aliphatic polyester) is used. ) Had a low melting point and was easily dissolved in an organic solvent, so that PVA was not thermally decomposed and the esterification reaction of PVA with a fatty acid was easy.

The releasable treating agent of the present invention comprises the above-mentioned reaction product and can be used in a solid form or a solution form. Further, upon forming a film of the release treatment agent, by crosslinking the hydroxyl groups in the copolymer with various crosslinking agents, a release layer having excellent heat resistance, mechanical strength, water resistance, solvent resistance, etc. is obtained. be able to. As the crosslinking agent, any polyfunctional compound that reacts with a hydroxyl group can be used. Specifically, for example, polyfunctional compounds such as phenol, melamine, epoxy, and isocyanate are suitable.

The release treating agent of the present invention is preferably used by dissolving the fatty acid-modified copolymer in a general-purpose solvent such as toluene, xylene and methyl ethyl ketone at a concentration of about 5 to 50% by weight. use, 0.01 to 1.0 g / m ² as solids, preferably 0.05 to 0.
5 g / m ² is applied to a support such as a plastic film, sheet, or tape to form a peelable film, sheet,
It can be used as a product such as tape, rubber-based,
It can be used as a peelable support such as an adhesive tape, an adhesive label, or an adhesive sheet using an acrylic or hot-melt adhesive or a pressure-sensitive adhesive.

[0027]

Next, the present invention will be described more specifically with reference to Production Examples, Examples and Comparative Examples. In addition, in sentences and tables, parts or%
Unless otherwise specified, the values are based on weight. Production Examples 1 to 3 As described in Table 1, PVA having a saponification degree of 98.5 mol%
(Polymerization degree 550), ε-caprolactone and a catalytic amount of tetrabutyl titanate are charged into a reaction vessel and heated at a rate of 1 ° C./2 to 3 minutes with stirring under a nitrogen stream. At 150 to 160 ° C., the reaction mixture which had been a heterogeneous system until then becomes gradually uniform, and at 180 to 200 ° C., it becomes a completely homogeneous system. The reaction is continued at 200 to 220 ° C. for 6 hours to obtain a PVA-based copolymer to which the aliphatic polyester used in the present invention is grafted.

[0028]

[Table 1]

Test Methods Tests for each physical property described in Table 1 were conducted by the following methods. * 1) Molecular weight: N, of the copolymer obtained in Production Examples 1 to 3
GPC measurement in N-dimethylformamide solution (5%). * 2) Hardness: 160 of the copolymer obtained in Production Examples 1 to 3
Press molding at a temperature of ℃ C, the obtained sheet is JIS K
It measured with the A type hardness meter based on -6301. * 3) 100% modulus (MPa), tensile strength (MP
a), elongation (%): The same press-formed sheet as used for the hardness measurement was punched out with a JIS K-7311 No. 3 dumbbell, and the physical properties were measured. * 4) Vicat softening point: JIS K-
7206.

Example 1 30 parts of the copolymer of Production Example 1 was dispersed in 70 parts of xylene, and 175 parts of stearic acid was added at reflux temperature to carry out an esterification reaction. When the desorbed water reaches the theoretical dehydration amount, 170
The produced water and excess stearic acid are removed under a reduced pressure of 10 ° C./10° C., and then the reaction product is poured into three times the amount of methanol to obtain a white precipitate. The white precipitate was washed and dried, and then pulverized to obtain a release treating agent of the present invention.

Example 2 A release treating agent of the present invention was obtained in the same manner as in Example 1 except that 30 parts of the copolymer, 70 parts of xylene and 185 parts of stearic acid were used. Example 3 A release treatment agent of the present invention was obtained in the same manner as in Example 1 except that 30 parts of the copolymer, 70 parts of xylene, and 195 parts of behenic acid were used.

Comparative Example 1 PVA (degree of saponification 98.5 mol%, degree of polymerization 550) 25
Parts, xylene 50 parts and stearyl isocyanate 16
Except for using 6 parts, a release treatment agent of a comparative example was obtained in the same manner as in Example 1 except for the above. Comparative Example 2 PVA (degree of saponification 98.5 mol%, degree of polymerization 550) 25
Parts, xylene 50 parts, docosanyl isocyanate 200
In the same manner as in Example 1, except that the above-mentioned parts were used, a release treatment agent of Comparative Example was obtained.

Performance test of peeling agent (1) Peeling force: Each of the peeling agents obtained in Examples 1 to 3 and Reference Examples 1 and 2 was dissolved in toluene at a concentration of 2% by weight. These solutions were respectively applied to the corona-treated surface of the OPP film and the untreated surface of the PET film so that the adhesion amount after drying was 0.1 g / m ² to form respective release layers. These peelable films have 25
mm pressure rubber adhesive tape (made by Nichiban) and acrylic adhesive tape (made by Sekisui Chemical) are pressed with a rubber roller of 2 kg in their own weight, and are pressed at room temperature (20 ° C., humidity 52%) and high temperature (50 ° C.). After storing for a period of time, the peeling force after leaving at room temperature for 2 hours was measured. The results are shown in Tables 2 and 3 below.

(2) Detachability: After the gauze was reciprocated 10 times under a load of 50 g / cm ^{2 on} each of the peelable treatment layers of the above-mentioned peelable film, the adhesion of the peelable treatment layer to the support was observed. The results are shown in Tables 2 and 3 below.・ ・ ・: No change. Δ: A part of the peelable treatment layer is seen to fall off. X: The peelable treatment layer was dropped.

(3) Adhesion: A 1 mm square cell was cut into 100 pieces with a knife on each of the release treatment layers of the release film.
An individual piece was peeled off using cellophane tape. The results are shown in Tables 2 and 3 below. (4) Storage property: Each 2% toluene solution of the releasable treating agent obtained in Examples 1 to 3 and Reference Examples 1 and 2 was placed at 5 ° C.
After storage for 3 days at 23 ° C. and 23 ° C., changes in the solution were observed. The results are shown in Tables 2 and 3 below.

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

EFFECTS OF THE INVENTION The release treating agent of the present invention is excellent in workability due to improvement in adhesion to a support, flexibility of a release layer, and solubility in a solvent.
Excellent peeling performance was exhibited even under the condition of ° C.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Katsumi Kuriyama, Inventor 1-7-6, Bakurocho, Nihonbashi, Chuo-ku, Tokyo Inside Dainichi Seika Kogyo Co., Ltd. (56) References JP-A-8-217820 (JP, A) Kaihei 7-109339 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08F 16/06 C08F 18/08 C08G 63/00-63/91

Claims (5)

(57) [Claims] 1. A releasable treating agent comprising a reaction product of a polyvinyl alcohol copolymer onto which an aliphatic polyester is grafted and a saturated fatty acid having 12 or more carbon atoms. 2. The release treatment agent according to claim 1, wherein the polyvinyl alcohol has a degree of saponification of 60 mol% or more. 3. The release treating agent according to claim 1, wherein the aliphatic polyester comprises a ring-opened polymer of polycaprolactone or polyvalerolactone. 4. The polyvinyl alcohol-based copolymer to which an aliphatic polyester is grafted has a molecular weight of 10,
The releasable treating agent according to claim 1, wherein the amount is from 000 to 500,000. 5. The binding amount of a saturated fatty acid having 12 or more carbon atoms is 50 to 50 parts by weight per 100 parts by weight of a polyvinyl alcohol-based copolymer onto which an aliphatic polyester is grafted.
The release treatment agent according to claim 1, wherein the amount is 500 parts by weight.