JPH09111197A - Pressure-sensitive adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a pressure-sensitive adhesive tape improved particularly in productivity, releasability (spreadability), adaptability to writing, slipperiness, etc., by providing a release agent layer formed from a specified water-dispersible release agent composition on the rear. SOLUTION: Pressure-sensitive adhesive tape is formed by providing a release agent layer on one side of a polystyrene or polycarbonate resin film and a pressure-sensitive adhesive layer on the other side thereof. The release agent layer is formed from a water-dispersible release agent composition consisting of a release agent obtained by reacting a vinyl acetate (co)polymer having a degree of polymerization of 300 to 5,000 and containing at least 50mol% vinyl alcohol units with a 6-30C long-chain alkyl compound having functional groups selected among isocyanate, carboxyl, acyl halide, ketene, aldehyde and epoxy groups and reactive with a hydroxyl group at an equivalent ratio of the hydroxyl groups of the (co)polymer to the functional groups of the alkyl compound of 1:(at least 0.5) and an acid-modified polyolefin copolymer having an acid value of 0.2 to 800 or a 10-30C fatty acid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive tape having a polystyrene resin or a polycarbonate resin as a base material and a release agent layer formed of a specific water-dispersed release agent composition provided on the back surface. In particular, the present invention relates to an adhesive tape having improved productivity, releasability (spreadability), writability, and slipperiness.

[0002]

2. Description of the Related Art Containers made of expanded polystyrene are widely used as transportation containers because they are excellent in water resistance, heat insulation and lightweight. In recent years, a polystyrene-based adhesive tape has been used in place of the polypropylene-based adhesive tape that has been conventionally used as the container closure and label. The reason for this is that when a container with an adhesive tape made of polypropylene or paper as a base material is collected and recycled, the adhesive tape base material remains as a foreign substance, resulting in deterioration of the quality of the polystyrene molded product after recycling. This is because it is easy to collect and recycle the expanded polystyrene container by using the same quality of base material.

[0003] Similarly, since a container made of polycarbonate is excellent in transparency, aroma barrier barrier property, heat resistance, and impact resistance, it is widely used as a packaging container for high temperature filling such as solid curry. If an adhesive tape made of a polycarbonate resin base material is used for sealing, lid sealing, labels, etc., collection and recycling will be easy. Also, the adhesive tape made of polystyrene resin or polycarbonate resin base material is
In addition to containers, general packaging of the same material, adhesion / joining / label / seal of building materials, surface protection materials such as transparent plates and press industrial products, adhesive industrial parts such as light diffusing materials for liquid crystal devices and phase difference plates, Used for electrical insulation.

Both the polystyrene resin film and the polycarbonate resin film have poor solvent resistance, and are generally used in the production and processing of tapes such as aromatic hydrocarbons such as toluene, ester organic solvents such as ethyl acetate, ketone solvents, etc. When it is attacked by the solvent used for the above, fine cracks are generated on the surface of the tape base material, and the tape base material is dissolved, swelled, and becomes cloudy to reduce the mechanical strength.

Therefore, as for the pressure-sensitive adhesive, it is possible to avoid the solvent-based one, use an emulsion-based or hot-melt-based pressure-sensitive adhesive, or apply the solvent-based pressure-sensitive adhesive directly to the tape substrate by a transfer method. A method of laminating after evaporating the solvent is adopted. However, the amount of the release agent applied to the base material is usually as small as a few g / m ² or less in solid content, and moreover, the release agent must be applied uniformly, so it is necessary to apply it directly to the base material. Therefore, it is difficult to apply the transfer method. Therefore, the organic solvent-based release agent becomes a problem especially for the substrate having poor solvent resistance.

[0006] As a means for solving this, Japanese Patent Laid-Open No. Hei 7
-76673 discloses an adhesive tape using a polystyrene resin film as a base material. This is a shellac layer formed on one surface of a polystyrene resin film substrate, a polymer having a long-chain alkyl group of an organic solvent system is applied as a release agent layer on this layer, and it is adhered to the other surface of the substrate. The agent is applied. Shellac is a natural resin with good adhesive properties, but it is a material that dissolves in monohydric alcohols but not in aromatic hydrocarbons or petroleum-based solvents. It is used as a base coat to prevent it from being dissolved. Although this method is generally applicable to polycarbonate resins having poor solvent resistance, it is necessary to add a step of applying shellac to a substrate.

As a solution other than the above method, an aqueous release agent has been proposed, which can be directly applied to a resin base material having poor solvent resistance. For example, JP-A-3-86778 discloses an aqueous release agent in which a long-chain alkyl graft polymer obtained by reacting polyvinyl alcohol or a modified product thereof with an alkyl isocyanate is emulsified and dispersed in water. ing. In addition, JP-A-6-73
Japanese Patent No. 351 discloses an aqueous release agent obtained by reacting a polyamine compound such as polyethyleneimine with a long-chain alkyl monoisocyanate.

[0008]

However, the above-mentioned water-based release agent must be heated for a long time after coating, as compared with the solvent-based release agent, in order to exhibit release performance and non-migration performance. In addition, there are problems, and the release performance and non-migration performance are insufficient compared to solvent-based release agents, and if the composition is changed to improve these performances, the stability of the water-based release agent is improved. However, there are also problems that the release agent is precipitated and aggregated, and the release agent cannot be dispersed in water. The present invention solves the above-mentioned problems of the water-based mold release agent, can release the mold release performance by heating for a short time after coating, does not cause aggregation or precipitation for a long time, and has excellent stability in water release system mold release. An agent composition was developed and applied to a polystyrene resin film or a polycarbonate resin film. As a result, the polystyrene resin film or the polycarbonate resin film was not dissolved, and the step of applying the undercoating agent was also unnecessary. Furthermore, the release agent having a long-chain alkyl group according to the present invention provides a releasable pressure-sensitive adhesive tape having appropriate release properties (spreading power) and writing properties that cannot be obtained with silicone-based release agents. did it.

[0009]

The pressure-sensitive adhesive tape of the present invention comprises:
In a pressure-sensitive adhesive tape comprising a polystyrene-based resin film or a polycarbonate resin film provided with a release agent layer on one side and an adhesive layer on the other side, the release agent layer has a polymerization degree of 300 to 5000. Yes, selected from the group of an isocyanate group, a carboxylic acid group, an acid halide group, a ketene group, an aldehyde group and an epoxy group with respect to 1 equivalent of a hydroxyl group of a vinyl acetate (co) polymer containing 50 mol% or more of a vinyl alcohol unit. And a release agent obtained by reacting a long-chain alkyl compound having a functional group capable of reacting with the above-mentioned hydroxyl group and having an alkyl group with 6 to 30 carbon atoms in terms of functional group in an amount of 0.5 equivalent or more, and an acid value. 0.2 to 800 acid-modified polyolefin copolymer, or 10 to 30 carbon atoms 1
It is formed from a water-dispersed release agent composition comprising one or more fatty acids.

The polystyrene resin film may be a film of polystyrene alone, but is preferably a blend with another polymer or a copolymer with another monomer in terms of physical properties as an adhesive tape substrate. . The polystyrene resin film is preferably stretched in terms of strength.

As the polycarbonate resin film,
It means a film of a polycondensation product of bisphenol A and phosgene, and the film may be produced by either an extrusion molding method or a solvent casting method, and may be stretched or non-stretched. In order to improve the adhesiveness, it is desirable that the tape base film be subjected to surface treatment such as corona discharge treatment.

Release Agent and Water-Dispersion-Based Release Agent Composition In the present invention, the water-dispersion-type release agent composition for forming the release agent layer is a release agent and an acid-modified polyolefin copolymer, or , Fatty acids. The release agent has a degree of polymerization of 300 to 50.
00, and a group of an isocyanate group, a carboxylic acid group, an acid halide group, a ketene group, an aldehyde group and an epoxy group with respect to 1 equivalent of a hydroxyl group of a vinyl acetate (co) polymer containing 50 mol% or more of a vinyl alcohol unit. A long-chain alkyl compound having a functional group capable of reacting with the above-mentioned hydroxyl group and having an alkyl group having 6 to 30 carbon atoms is obtained by reacting 0.5 equivalent or more in terms of a functional group. .

The vinyl acetate (co) polymer before saponification, which is a material for one of the reaction components forming the release agent, may be a homopolymer of vinyl acetate, or a copolymer of vinyl acetate and another vinyl compound. However, examples of the copolymer include vinyl acetate-ethylene copolymer and vinyl acetate-acrylic acid copolymer. If the degree of polymerization of the vinyl acetate (co) polymer before saponification is too low, the release performance will be poor, and if it is too high, the release agent component will be difficult to disperse in water, so it is limited to 500 to 3000, Preferably 800-
2500.

The vinyl acetate (co) polymer is saponified and the vinyl acetate portion is converted into vinyl alcohol for use. However, if the amount of the vinyl alcohol portion in the copolymer is too small,
Since the amount of hydroxyl groups capable of reacting is insufficient and the releasing performance of the releasing agent obtained by using this saponified product is lowered, the amount of vinyl alcohol unit is 50 mol% or more, preferably 60 mol% or more.

The long-chain alkyl compound as the other reaction component forming the release agent has 6 to 30 carbon atoms in the long-chain alkyl group and has a functional group reactive with the hydroxyl group bonded thereto. is there. If the carbon number is less than 6, the release performance will be poor. It is preferably 8 or more. Examples of the functional group that reacts with a hydroxyl group include an isocyanate group, a carboxylic acid group, an acid halide group, a ketene group, an aldehyde group and an epoxy group.

The long-chain alkyl compounds include, for example, those having an isocyanate group such as octyl isocyanate, dodecyl isocyanate, octadecyl isocyanate, docosanyl isocyanate; those having a carboxylic acid group such as octanoic acid, dodecanoic acid, octadecanoic acid and docosane. Acids and the like; those having an acid halide group, such as octanoyl chloride, dodecanoyl chloride, and docosanoyl chloride; those having a ketene group, such as octyl ketene dimer, dodecyl ketene dimer, octadecyl ketene dimer, docosanyl ketene dimer; As those having a group, octyl aldehyde, dodecyl aldehyde, octadecyl aldehyde, docosanyl aldehyde, etc .; Glycidyl ether, dodecyl glycidyl ether, octadecyl glycidyl ether,
Examples thereof include docosanyl glycidyl ether.

The long-chain alkyl compound is reacted with the hydroxyl group of the partially saponified vinyl acetate (co) polymer to obtain a release agent. In this reaction, if the proportion of the long-chain alkyl compound decreases, the mold release performance deteriorates. Therefore, the reaction proportion of the long-chain alkyl compound that makes one equivalent of the hydroxyl group of the vinyl acetate copolymer is
0.5 equivalent or more in terms of functional group, preferably 0.6
It is more than equivalent.

The acid-modified polyolefin (co) polymer release agent used in combination with the acid-modified polyolefin copolymer is
A polyolefin copolymer having an acid value of 0.2 to 800, for example, an olefin such as ethylene, propylene and 1-butene, and a polar group such as acrylic acid, methacrylic acid, maleic acid, itaconic acid and vinylpyrrolidone. And a copolymer with a vinyl monomer having

The acid value of the acid-modified polyolefin copolymer is
If it is too small, it will be difficult to disperse in water, and it will easily aggregate and settle,
If it is too large, it is separated from the release agent, so that a material having a content of 0.2 to 800 is used, and a content of 10 to 20 is preferable. In the case of a copolymer with a vinyl monomer having a polar group, the copolymerization amount of the polar vinyl monomer is preferably 0.01 to 40 mol%, more preferably 0.5 to 10 mol%.
It is.

If the degree of polymerization of the acid-modified polyolefin copolymer is too high, it is difficult to disperse in water, and the water-dispersed release agent composition is applied to a polystyrene resin film base material or a polycarbonate resin film base material, and then released. Before the mold performance is exhibited, unfavorable effects such as heating for a long time appear, and if the degree of polymerization is too low, it becomes a softened state even at room temperature and adversely affects the mold release performance. It is preferably 20 to 1000.

Regarding the melting point and melt viscosity of the acid-modified polyolefin copolymer, if the melting point is too low, the releasing performance is adversely affected, and if the melt viscosity at high temperature is too high, it becomes difficult to disperse in water. When a water-dispersed release agent composition is applied to a polystyrene resin film or a polycarbonate resin film and the release performance is exhibited, heating takes a long time and an unfavorable effect appears. Therefore, the melting point is 40
℃ or more, the melt viscosity at 140 ℃ is 10,000
It is preferably Pa · s or less, and more preferably has a melting point of 60 ° C. or higher and a melt viscosity at 140 ° C. of 500.
It is 0 Pa · s or less. Examples of such an acid-modified polyolefin copolymer include maleic acid-modified polyethylene wax and acrylic acid-modified polyethylene wax.

The fatty acids used in combination with the fatty acid release agent are saturated fatty acids and unsaturated fatty acids having 10 to 30 carbon atoms, and these may be used alone or as a mixture. If the carbon number of the fatty acid is too large, the polarity becomes too low and it becomes difficult to disperse in water, or the solution viscosity becomes too high and the water-releasing release agent composition is applied to the substrate, and then the release performance is improved. Has an unfavorable effect such as heating for a long period of time until the expression of. On the other hand, if the carbon number is too small, the polarity becomes too high to separate from the release agent component, or the melting point becomes low, which adversely affects the release performance. Therefore, the carbon number of the fatty acid is in the range of 10 to 30, preferably 12 to 26.

Examples of such fatty acids include dodecanoic acid (lauric acid), hexadecanoic acid (palmitic acid), octadecanoic acid (stearic acid), octadecenoic acid (oleic acid), icosanoic acid (arachidic acid), and docosanoic acid ( Behenic acid) and the like.

The fatty acid may be in the form of a metal salt in the presence of a hydroxide of an alkali metal or alkaline earth metal such as sodium hydroxide or barium hydroxide. The fatty acid so-called includes fatty acids in such a state.

Further, when the amount of the fatty acid compounded is small, it becomes difficult to emulsify and disperse the release agent component in water when the water-dispersed release agent is produced, and when it is increased, the water-dispersed mold release agent using the same is used. When the agent is used, unfavorable effects such as strong migration to the pressure-sensitive adhesive layer appear, so the release agent component 100
The amount is preferably 1 to 50 parts by weight, and more preferably 3 to 40 parts by weight.

It is optionally added to the water-dispersed release agent composition.
Additives The water-dispersed release agent composition used in the present invention facilitates dispersing the resin in water, or the water-dispersed release agent composition is applied to a polystyrene resin film or a polycarbonate resin film. To improve coatability when
For the purpose of suppressing foaming, it is possible to add a liquid substance having a high boiling point, a surfactant, or a crosslinking agent for increasing the film strength after coating.

The liquid substance having a high boiling point has a boiling point at atmospheric pressure higher than 100 ° C. and a viscosity at room temperature of 1000 Pa · s.
The following substances are preferred. Furthermore, if a high-boiling-point liquid substance is contained in the pressure-sensitive adhesive, the high-boiling-point liquid substance remains in the coating film obtained by coating and drying the water-dispersed release agent composition. Even if it shifts to the pressure-sensitive adhesive layer, the pressure-sensitive adhesive performance of the pressure-sensitive adhesive is not significantly impaired, which is preferable.

The liquid substance having a high boiling point is a substance usually used as a softening agent in an adhesive, and examples thereof include naphthenic oil, lanolin, oligomers of olefins, vegetable oil,
Process oils such as animal oils, mineral oils (petroleum), long-chain alkylcarboxylic acids, long-chain alkyl alcohols, liquid tackifying resins such as liquid rosin and turpentine oil, and plasticizers such as polybutene, polyisobutylene and diisodecyl phthalate. . When these substances have a boiling point of 100 ° C. or less, they are volatilized during drying, which causes safety and environmental problems. When the viscosity is higher than 1000 Pa · s, the fluidity is low and the effect of improving the film forming property is small.

As the surface active agent, nonionic surface active agents, anionic surface active agents, cationic surface active agents, amphoteric surface active agents and the like can be used. Examples of nonionic surfactants include ether types such as polyoxyethylene alkylphenyl ether and polyoxyethylene alkyl ether, ester types such as glycerin fatty acid ester, sorbitan fatty acid ester, and sucrose fatty acid ester, polyethylene glycol fatty acid ester, poly Examples thereof include ester ether type such as oxysorbitan fatty acid ester and fatty acid alkanolamide type.

Examples of the anionic surfactant include:
Carboxylic acid type such as fatty acid monocarboxylic acid salt and N-acryloylglutamate, alkylbenzene sulfonate,
Examples thereof include naphthalene sulfonate-formaldehyde condensate, sulfonic acid type such as sulfosuccinic acid dialkyl ester, sulfuric acid ester type such as alkyl sulfate salt, and phosphoric acid ester type such as alkyl phosphate salt.

As the cationic surfactant, for example,
Examples thereof include amine salt types such as alkylamine salts, and quaternary ammonium salts such as alkyltrimethylammonium salts and alkyldimethylbenzylammonium salts.

As the amphoteric surfactant, for example, N, N
Examples include carboxybetaine type such as dimethyl-N-alkylaminoacetic acid betaine and glycine type such as 2-alkyl-1-hydroxyethyl-1-carboxymethylimidazolinium betaine.

Any crosslinking agent may be used as long as it reacts with the release agent by heat, light or the like during the film formation after coating to cause crosslinking. Specific examples include polyvalent isocyanate compounds, blocked polyvalent isocyanate compounds, polyvalent epoxy compounds, polyvalent acryloyl compounds, polyvalent methylol compounds, polyvalent metal ions, and polyvalent aziridine compounds.

Method for producing coating liquid of water-dispersed release agent composition The coating liquid of the water-dispersed release agent composition used in the present invention comprises a release agent and an acid-modified polyolefin copolymer or a fatty acid. After dissolving in an organic solvent, mix with water while stirring with a high-speed emulsifying machine to emulsify and disperse, and then use a solvent dissolution method excluding the organic solvent, or without using an organic solvent, the release agent and the acid-modified polyolefin copolymer It can be obtained by a high-pressure emulsification method in which a coalesced product or a fatty acid is heat-melted and mixed with water while being highly sheared by a pressure kneader, a colloid mill, a high-speed stirring shaft, or the like and emulsified and dispersed.

As for the mixing ratio of the water-dispersed release agent composition and water during emulsification and dispersion, if the content of the water-dispersed release agent composition is too small, the shearing effect is reduced and the production efficiency is lowered. When the content of the water-dispersion release agent composition is too large, the viscosity becomes too high, and it becomes difficult to emulsify and disperse by shearing. Therefore, the content of the water-dispersion release agent composition is 5 to 50% by weight. It is preferable that After the emulsification and dispersion, it may be optionally diluted with water as long as the stability of the water-dispersed release agent is not impaired.

Of the above methods, the high pressure emulsification method is preferable because it does not require the use of a deorganization solvent and the process can be simplified. The high pressure emulsification method is performed as follows, for example.
A solution obtained by melt-mixing a release agent and an acid-modified polyolefin copolymer or a fatty acid at 120 ° C. or higher, and applying pressure to 10
Water heated to 0 ° C. or higher is mixed while applying high shear to disperse the solution in water, and then cooled so that the dispersed particles do not melt and aggregate. Alternatively, a mold release agent and an acid-modified polyolefin copolymer or a fatty acid are simultaneously added to water and dispersed under high pressure at 120 ° C. under high shear.

Coating of Water-Dispersion Release Agent Composition Before coating a coating solution of the water-dispersion release agent composition on the surface of a polystyrene resin film or a polycarbonate resin film, the wettability of the film surface is increased, Corona discharge treatment to prevent repellency and enhance adhesion after drying,
It is preferable to perform plasma treatment or the like. Corona discharge treatment, plasma treatment, the film surface is generally
Perform with standard wetting reagent until 40 dyn / cm or more.

The coating of the water-dispersed release agent composition is carried out by using a general coating apparatus such as a roll coater, a gravure coater, a Meyer bar coater and a lip coater. However, if the coating amount is too small, the release agent composition is released. Since the moldability is poor and peeling is difficult, and when the amount is too large, the adhesive performance of the adhesive decreases with time, and the cost also increases, so the solid content after drying is 0.05 to 0.5 g / m ^2. Is preferred.

Formation of Releasing Agent Layer A coating solution prepared by diluting a water-dispersed releasing agent composition in a predetermined amount is directly and uniformly applied to the surface-treated film surface to prevent deterioration of the film substrate. And dried for a short time to form a release agent layer firmly adhered to the film substrate.

Formation of Pressure-Sensitive Adhesive Layer In the present invention, a pressure-sensitive adhesive layer is laminated on the surface of the polystyrene resin film or polycarbonate resin film opposite to the release agent layer. For the pressure-sensitive adhesive layer, a commonly used rubber-based pressure-sensitive adhesive, acrylic pressure-sensitive adhesive or the like can be used. When the transfer method is used as the coating method, there is no need to consider the possibility of dissolution by a solvent. Further, a non-solvent adhesive, a styrene resin, or an adhesive made of a solvent that does not corrode a polycarbonate substrate (normal hexane, heptane, etc.) can be directly applied.

(Function) In the pressure-sensitive adhesive tape of the present invention, as a releasing component, a saponification product of vinyl acetate (co) polymer containing 50 mol% or more of a vinyl alcohol moiety, and a reaction with a hydroxyl group of the saponification product. 6 to 3 carbon atoms having a functional group to
A water-dispersion system comprising a releasing agent obtained by reacting a long-chain alkyl compound of 0 and an acid-modified polyolefin copolymer having an acid value of 0.2 to 800, or a fatty acid having 10 to 30 carbon atoms. Since the release agent composition is used, it has stable release properties and does not dissolve the polystyrene resin film or the polycarbonate resin film. Therefore, it is not necessary to apply an undercoat on the surface on which the release agent layer made of the water-dispersed release agent composition is formed. Further, since the release agent is composed of a reaction product of a partially saponified vinyl acetate (co) polymer and a long chain alkyl compound, it can be imparted with a layering property, a writing property and a frictional force. Further, a container made of polystyrene resin or polycarbonate resin and having an adhesive tape of the same material attached thereto can be reprocessed as it is.

[0042]

Embodiments of the present invention will be described below. Example 1 Synthesis of Release Agent (R1) Polyvinyl alcohol dispersed in 50 g of dehydrated xylene (polymerization degree 1100, vinyl alcohol unit 9)
8 mol%) 10 g octadecyl isocyanate 67 g
And 0.01 g of catalyst (dibutyltin dilaurate) are added,
It was reacted with the above polyvinyl alcohol. The reaction solution was poured into 1000 g of methanol to obtain a white precipitate, which was washed with methanol and then with hexane, and dried to obtain a release agent (R1).

Coating liquid of water-dispersed release agent composition (R _A ) Release agent (R1) 1 heated to 130 ° C. in a high-pressure emulsifier
According to the following formulation ( _RA ), 5 g was slowly dropped into pressurized water, and the mixture was stirred at 5000 rpm for 1 hour at high speed to emulsify and then cooled to obtain a coating liquid of the water-dispersed release agent composition. Obtained. When the stability of the coating liquid of the obtained water-dispersed release agent composition was evaluated, it was stable without sedimentation or aggregation for a long period of time. Composition of coating liquid of water-dispersed release agent composition ( _RA ) Release agent (R1) 15 g Acid-modified polyolefin (ethylene-acrylic acid copolymer) 4 g Surfactant 1 g Oil component (1-decanol) 4 g Water 76 g

Coating liquid (R _A ) of the above water-dispersed release agent composition
Was diluted with water so that the release agent (R1) was 3% by weight. This was coated on one surface of a biaxially stretched polystyrene film (made by Asahi Kasei Co., Ltd.) having a thickness of 40 μm so as to be about 8 g / m ² , heated and dried to form a release agent layer. The drying conditions are 120 ° C. and 60 seconds. Then, on the other surface of the film, 25 μm of an acrylic adhesive composed of the following monomer composition was used.
A m-thick coating was applied by a transfer method to obtain an adhesive tape. Composition of acrylic adhesive 2-ethylhexyl acrylate 70 parts by weight Vinyl acetate 30 parts by weight Acrylic acid 2 parts by weight

Example 2 An adhesive tape was obtained in the same manner as in Example 1 except that a polycarbonate film having a thickness of 30 μm was used instead of the biaxially stretched polystyrene film having a thickness of 40 μm.

Example 3 An adhesive tape of polystyrene film was obtained in the same manner as in Example 1 except that the composition of the adhesive was changed to the SIS type adhesive. Blending of SIS-based adhesive Styrene-isoprene-styrene copolymer (SIS) 100 parts by weight Hydrogenated rosin ester 100 parts by weight Process oil 20 parts by weight Anti-aging agent 5 parts by weight

Example 4 3 g of stearic acid instead of the acid-modified polyolefin resin
The release agent composition using is melted at 120 ° C., 500 rp
Mixing was carried out with stirring at a rotation speed of m for 10 minutes. This mixture was emulsified and cooled in the same manner as in Example 1 to obtain a coating liquid of the water-dispersed release agent composition. When the stability of the obtained water-dispersed release agent coating liquid was evaluated, it was stable for a long period of time without sedimentation or aggregation.

Next, the coating liquid of this water-dispersed release agent composition was diluted with water so that the release agent was 3% by weight, and this was subjected to corona discharge treatment (44 dyn / cm) to obtain a polystyrene resin. After drying with # 5 Meyer bar coater on one side of the film, it was applied to 0.3 g / m ² ,
It was dried to form a release agent layer. Then, an adhesive was applied to the other surface of the polystyrene resin film in the same manner as in Example 1 to obtain an adhesive tape.

Example 5 An adhesive tape was obtained in the same manner as in Example 4 except that the polycarbonate resin film having a thickness of 30 μm (manufactured by Teijin Ltd.) was used as the base material, the polystyrene resin film.

Comparative Example 1 , Solvent type silicone release agent A release agent comprising 100 parts by weight of silicone, 1000 parts by weight of normal hexane, 200 parts by weight of toluene, and 5 parts by weight of catalyst was used as one side of a polystyrene resin film or a polycarbonate resin film. To about 2 g / m ² each, and
Adhesive tapes were produced in the same manner as in Example 1 except that the release agent layer was formed by drying at 0 ° C. for 2 seconds, but all the tapes were cut by the organic solvent during deceleration during production. Moreover, the release agent layer of the obtained adhesive tape could not be written with a felt-tip pen using an oil-based ink.

Comparative Example 2 As a releasing agent, a long-chain alkyl releasing agent (R1) was dissolved in toluene, and the coating amount after drying was 0.4 g / solid.
In the same manner as in Example 1 except that a polycarbonate film having a thickness of 30 μm was coated so that the thickness became m ² .
An adhesive tape was produced.

Comparative Example 3 Example 1 was repeated, except that a long-chain alkyl releasing agent was dissolved in a mixed solvent of normal hexane and heptane, and the solution was coated so as to be 0.4 g / m ² after drying. An adhesive tape was obtained in the same manner as in, but a large-scale solvent gas recovery device was required to recover the solvent gas generated during the production.

Comparative Example 4 Shellac was coated at ² g / m ^{2 on the} same polystyrene resin film as used in Example 1, and the same release agent as used in Comparative Example 1 was coated thereon. A rubber-based pressure-sensitive adhesive having the following composition was applied on the opposite side of the film to a thickness of 30 μm to obtain a pressure-sensitive adhesive tape. Rubber-based adhesive compounding Natural rubber 50 parts by weight C5-based petroleum resin 40 parts by weight Process oil 10 parts by weight Normal hexane 300 parts by weight Toluene 10 parts by weight This product did not cause any trouble in manufacturing,
The productivity was low because a step of applying shellac as an undercoat was required, and it was not environmentally friendly because an organic solvent was used to apply silicone.

Performance Evaluation The adhesive tapes of Examples 1 to 5 and Comparative Examples 1 to 4 were evaluated for performance by the following method. (1) Releasability (expanding force) The adhesive tape was cut into a width of 15 mm, and JIS Z-023 was used.
The peeling force when rewinding at a speed of 10 m / min in accordance with 7 is defined as the deploying force. If this measured value is small, the mechanical suitability will deteriorate. (2) Writability (sliding property) A character was written on the surface of the release agent layer with a felt-tip pen using an oil-based ink, and after being left at room temperature for 5 seconds, the character was not scratched, smudged, or repelled, or rubbed with a finger. At this time, the state of ink dropout was observed. ○: Scratch, bleeding, and repellency ×: No blur, bleeding, and repellency (3) Use of organic solvent ○: None ×: Yes (4) Recyclability (whether melting / regeneration at the time of collection after use) ○ : No problem x: Occurrence of clogging after collection, deterioration of quality of recycled product (5) Trouble in manufacturing When the release agent was applied, the organic solvent slowed down, and deterioration or breakage of the film was observed at the time of stopping. ◯: No problem x: Deterioration / cutting occurred Table 1 shows the above results.

[0055]

[Table 1]

As is clear from Table 1, in each of Examples 1 to 5, the releasability was good, and all other evaluation items were also good results. However, in the case of Comparative Examples 1 to 4,
It is understood that all of them are inferior in releasability (spreadability).

[0057]

EFFECT OF THE INVENTION Since the pressure-sensitive adhesive tape of the present invention has the above-mentioned constitution, it is excellent in mold release performance (spreadability) and is coated with an undercoat as a base material protection when an organic solvent type mold release agent is used. There is no need to do it, no environmental problems, and high productivity. or,
When used as a container for sealing expanded polystyrene resin or polycarbonate resin containers or as a label, it can be easily melted and regenerated after collection, the writing property of the release agent layer surface of the adhesive tape, and an appropriate release property at the time of application (development) It is also excellent in sex.

Claims (1)

[Claims] 1. A release agent layer is provided on one surface of a polystyrene resin film or a polycarbonate resin film,
In an adhesive tape having an adhesive layer provided on the other surface, the release agent layer has a degree of polymerization of 300 to 5000,
Isocyanate group, carboxylic acid group, acid halide group, ketene group, per 1 equivalent of hydroxyl group of vinyl acetate (co) polymer containing 50 mol% or more of vinyl alcohol unit,
It has a functional group which is selected from the group of aldehyde groups and epoxy groups and reacts with the above-mentioned hydroxyl groups, and the alkyl group has 6 to 6 carbon atoms.
A releasing agent obtained by reacting a long-chain alkyl compound of 30 with 0.5 equivalent or more in terms of functional group, and an acid value of 0.2 to 80
0 acid-modified polyolefin copolymer or 1 carbon number
An adhesive tape comprising a water-dispersed release agent composition comprising one or more fatty acids of 0 to 30.