JPH07233356A - Production of water-soluble adhesive tape - Google Patents

Abstract

PURPOSE:To obtain the subject type useful as a masking tape and a transferring tape of high adhesion to the support and substrate, readily soluble in water of a variety of pH, by effecting photopolymerization after the support is coated with a specific polymerizing composition, then heat-drying. CONSTITUTION:The substrate is coated with a polymerizing composition comprising (A) a polymerizable monomer containing a phosphate ester of (meth)acrylate bearing terminal hydroxyls, for example, 2-hydroxyethyl (meth)acrylate phosphate, (B) an alkaline neutralizing agent such as sodium hydroxide or ammonia (C) a photopolymerization initiator such as 4-(hydroxyethoxy)phenyl-(2-hydroxy-2- propyl)ketone and (D) an organic solvent such as ethanol, ethyl acetate, acetone, THF or the like on at least one surface. The coated layer is subjected to photopolymerization and dried with heat to give the object tape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a water-soluble pressure-sensitive adhesive tape using a pressure-sensitive adhesive which is soluble in any of acidic water, neutral water and alkaline water.

2. Description of the Related Art Conventionally, a water-soluble adhesive having a normal tackiness is a paper which is fixed in the paper manufacturing industry with a water-soluble adhesive, spliced, and then returned to the pulp dissolving tank for reuse. Widely used as a splicing tape for recycling and as an adhesive for labels such as bottles and foods in the food industry, especially as an adhesive for labels that makes it easy to remove the label by washing with water when it is no longer needed. Has been.

On the other hand, in the field of electronic materials, various adhesive tapes are used in the manufacturing process thereof, and examples thereof include masking tapes for metal plating of printed circuit boards and electronic parts, and carrier tapes for carrier of chips. These tapes are generally temporary adhesive tapes and are often peeled off from the adherend after use. Therefore, the releasability of the adhesive is required, and it is necessary to have the performance that the adhesive component does not remain on the surface of the adherend during peeling (adhesive residue phenomenon) and does not contaminate the adherend, especially for precision products. , A very small amount of glue residue is not allowed. Conventionally, in such an application, after removing the adhesive tape, the adherend is washed with an organic solvent to remove the residual adhesive residue. However, in recent years, from the viewpoint of global environmental protection, the movement to switch to washing with water instead of using an organic solvent has become active, and the adhesive used for the adhesive tape is also required to be washable with water. .

Examples of the water-soluble or water-washable pressure-sensitive adhesive as described above include Japanese Patent Publication No. 49-23813, Japanese Patent Publication No. 50-34578 and Japanese Patent Publication No. 52-22.
As disclosed in, for example, Japanese Patent Publication No. 768, these use a specific carboxyl group-containing polymer or a water-soluble polymer salt such as an alkali metal salt, an amine salt or an alkanolamine salt as a polymer component, Polyether polyol, polyhydric alcohol,
It has a constitution in which a water-soluble or water-dispersible plasticizer such as an alkanolamine salt of acidic rosin is blended. However, these conventional water-soluble pressure-sensitive adhesives use a polymer having a strong polarity such as vinylpyrrolidone and a high glass transition temperature above room temperature as a carboxy-containing polymer in order to impart water solubility, and plasticize the same. In order to impart tackiness by converting the polymer component and the water-soluble or water-dispersible plasticizer into a large amount, a liquid water-soluble or water-dispersible plasticizer having a relatively low molecular weight is blended. There is a problem in that the plasticizer is leached out with time and the adhesive strength is reduced, or the plasticizer migrates to the adherend to contaminate the adherend or deteriorates the physical properties of the adherend. there were.

Further, the support used for the removable tape such as the above-mentioned plating masking tape has a tensile strength capable of withstanding the peeling stress applied at the time of re-peeling and is immersed or exposed in acidic water, neutral water or alkaline water. Since it is required that the strength does not decrease remarkably even if it is applied, plastic films such as polyester film, polyethylene film, polypropylene film, polyacetate film, polyamide film, acetyl cellulose film and the like are frequently used. Generally, these plastic films are hydrophobic, whereas the water-soluble pressure-sensitive adhesive is hydrophilic, so that the water-soluble pressure-sensitive adhesive wets the plastic film poorly and has poor adhesiveness. As a countermeasure against this, the treated surface of a plastic film which has been subjected to surface oxidation treatment such as corona treatment has a primary amino group,
A water-soluble pressure-sensitive adhesive tape substrate coated with a modified polyacrylic acid ester and / or modified polyester resin-based undercoating agent (primer) having a g of -80 to 120 ° C has been proposed (see Japanese Patent Application No. 4-303583). ). However, in the case of this method, problems such as complication of the process and cost increase accompanying the undercoating agent, and the adhesive force between the plastic film and the pressure-sensitive adhesive may increase or decrease with time depending on the type of the undercoating agent. There are problems such as changes in tape performance.

As one method for increasing the adhesiveness between a plastic film and a pressure-sensitive adhesive without applying an undercoating agent, a polymerizable monomer serving as a base of a polymer constituting the pressure-sensitive adhesive is directly coated on the plastic film, A method of obtaining an alkali water-soluble adhesive tape by irradiating and polymerizing has been proposed (see Japanese Patent Application No. 4-303582). However, the photopolymerization method has a drawback that the heat generation during the polymerization is high because the polymerization proceeds rapidly, and the monomer composition having a low boiling point is volatilized to change the monomer composition.Therefore, a heat removal device is provided in the polymerization zone. The need arises, and there are problems such as increased capital investment and reduced tape productivity.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention dissolves in any of acidic water, neutral water and alkaline water, and has adhesiveness to a support and an adherend. It is an object of the present invention to provide a method for producing a water-soluble pressure-sensitive adhesive tape using a pressure-sensitive adhesive that is excellent in heat generation and generates less heat during photopolymerization.

[0007]

The method for producing a water-soluble pressure-sensitive adhesive tape according to the present invention comprises a polymerizable monomer containing a phosphate ester of (meth) acrylate having a terminal OH group as an essential component,
Alkaline neutralizing agent, a polymerizable composition containing a photopolymerization initiator and an organic solvent, coated on at least one side of the support,
It is characterized in that it is heated and dried after photopolymerization, whereby the above object is achieved. In the present invention,
(Meth) acrylic means acrylic or methacrylic.

The pressure-sensitive adhesive used in the method for producing the water-soluble pressure-sensitive adhesive tape of the present invention is a polymerizable monomer containing a phosphoric acid ester of (meth) acrylate having a terminal OH group as an essential component, an alkaline neutralizing agent, a photopolymerization initiator. It is obtained by photopolymerizing a polymerizable composition containing an organic solvent and an organic solvent, followed by heating and drying.

The phosphoric acid ester of (meth) acrylate having a terminal OH group can be obtained by reacting (meth) acrylate having a terminal OH group with phosphoric acid to form an ester.

The type of (meth) acrylate having a terminal OH group is not particularly limited, but examples thereof include 2-hydroxyethyl (meth) acrylate and 2-hydroxyethyl (meth) acrylate.
One of the OH groups of the alkanediol such as hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate is esterified with (meth) acrylic acid. Compounds, polyalkylene glycol (meth) acrylates such as diethylene glycol (meth) acrylate, totaethylene glycol (meth) acrylate, dipropylene glycol (meth) acrylate and 2-acryloyloxyethyl-2-hydroxypropyl phthalate, 2- Examples thereof include those having an aromatic ring such as hydroxy-3-phenoxypropyl (meth) acrylate. One or two or more of these esterified with phosphoric acid by a conventional method are the above-mentioned polymerizable monomers. It is preferably used as the main component.

In the present invention, in addition to the above-mentioned phosphoric ester of (meth) acrylate having a terminal OH group as the polymerizable monomer, alkyl (meth) is used for improving the tackiness and flexibility of the pressure-sensitive adhesive. Acrylate may be contained. The alkyl group of the alkyl (meth) acrylate preferably has 2 to 12 carbon atoms,
Especially, it is more preferable that it is 2-8. When the number of carbon atoms in the alkyl group is greater than 1 or 12, the elastic modulus of the resulting polymer may be too high and the pressure-sensitive adhesive may be hard. Alkyl having 2 to 12 carbon atoms (alkyl)
As the acrylate, for example, ethyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, Octyl (meth) acrylate, dodecyl (meth) acrylate, etc. are mentioned, and these 1 type (s) or 2 or more types are used suitably.

The content of the above-mentioned alkyl (meth) acrylate is not particularly limited, but the total amount of the phosphoric acid ester of (meth) acrylate having a terminal OH group and the alkyl (meth) acrylate is 100 parts by weight. ,
The amount of alkyl (meth) acrylate is preferably about 50 parts by weight or less. When the content of the alkyl (meth) acrylate exceeds about 50 parts by weight, the pressure-sensitive adhesive obtained may have poor water solubility.

Further, in the present invention, in addition to the phosphoric ester of (meth) acrylate having a terminal OH group and the above alkyl (meth) acrylate as the polymerizable monomer, in order to further improve the water solubility of the pressure-sensitive adhesive, A carboxyl group-containing monomer may be contained. Examples of the carboxyl group-containing monomer include (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, 2-acryloyloxyethyl (propyl)
Examples thereof include phthalic (succinic) acid and hydrogenated products thereof, β-acryloxypropionic acid, polycaprolactone acrylate, and the like, and one or more of these are preferably used.

The content of the above-mentioned carboxyl group-containing monomer is not particularly limited, but with respect to a total amount of 100 parts by weight of a phosphoric ester of (meth) acrylate having a terminal OH group and an alkyl (meth) acrylate, The amount of the carboxyl group-containing monomer is preferably about 100 parts by weight or less. When the content of the carboxyl group-containing monomer exceeds about 100 parts by weight, the resulting pressure-sensitive adhesive may become hard and may have poor adhesiveness, which is not preferable.

Further, in the present invention, as the polymerizable monomer, other than the phosphoric acid ester of (meth) acrylate having a terminal OH group, the alkyl (meth) acrylate and the above-mentioned carboxyl group-containing monomer, other polymerizable monomers may be used as necessary. A vinyl-based monomer may be contained. Examples of other vinyl-based monomers include vinyl acetate, styrene, N-vinylpyrrolidone, N, N-dimethylaminoethyl (meth) acrylate, acrylonitrile, and 2
-Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, polyethylene glycol (meth) acrylate, methyl methacrylate macromonomer, styrene macromonomer and the like can be mentioned, and one or more of these are preferably used. To be

The content of the other vinyl-based monomer is not particularly limited, but is 100 parts by weight with respect to the total amount of the phosphoric acid ester of (meth) acrylate having a terminal OH group and the alkyl (meth) acrylate. The amount of the other vinyl-based monomer is preferably about 50 parts by weight or less. When the content of the other vinyl-based monomer exceeds about 50 parts by weight, when the other vinyl-based monomer is water-insoluble, the resulting adhesive may have poor water solubility. Is water-soluble, the resulting pressure-sensitive adhesive may be affected by moisture in the air, resulting in impaired water resistance.

In the polymerizable composition used in the method for producing the water-soluble pressure-sensitive adhesive tape of the present invention, the acid group in the polymerizable monomer is neutralized in advance to impart water solubility to the obtained pressure-sensitive adhesive. It is necessary that the polymerizable composition contains an alkaline neutralizing agent.

The alkaline neutralizing agent is not particularly limited, but inorganic alkalis such as potassium hydroxide, sodium hydroxide, potassium hydrogen carbonate, sodium hydrogen carbonate, and ammonia, alkylamines, alkanolamines, Examples thereof include organic alkalis such as pyridines, pyrrolidines, and pyrrolidones, and one or more of these are preferably used.

The content of the alkaline neutralizing agent is not particularly limited, but the alkaline neutralizing agent is contained in an amount of 10 to 300 mol% based on the total number of moles of the acid groups in the polymerizable monomer.
The amount is preferably about 20 to 150 mol%, and more preferably about 20 to 150 mol%. If the content of the alkaline neutralizing agent is less than about 10 mol%, the neutralization will be insufficient and the resulting pressure-sensitive adhesive will dissolve in alkaline water, but it will be difficult to dissolve in acidic water and neutral water. is there. On the other hand, when the content of the alkaline neutralizing agent exceeds about 300 mol%, the cohesive force of the obtained pressure-sensitive adhesive is impaired and cohesive failure occurs when re-peeling, or the alkaline neutralizing agent bleeds out to the adhesive interface. As a result, the adherend may be corroded or the electrical characteristics may be deteriorated.

The photopolymerization initiator contained in the polymerizable composition used in the method for producing the water-soluble pressure-sensitive adhesive tape of the present invention is not particularly limited, but 4- (hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, α-hydroxy-α, α'-dimethyl-acetophenone, methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone and other acetophenone-based photopolymerization initiators, benzyl ketal and other ketal-based Examples include various photopolymerization initiators such as photopolymerization initiators, halogenated ketones, acyl phosphinoxides, and acyl phosphonates, and one or more of these are preferably used.

The content of the photopolymerization initiator varies depending on the type and reactivity of the polymerizable monomer, the molecular weight and the molecular weight distribution of the target pressure-sensitive adhesive, and is not particularly limited, but is generally. The amount of the photopolymerization initiator is preferably about 0.01 to 1 part by weight based on 100 parts by weight of the total amount of the polymerizable monomers. If the content of the photopolymerization initiator is less than about 0.01 parts by weight, the polymerization may not proceed sufficiently, and conversely 1
If the amount exceeds about parts by weight, the polymerization may proceed too rapidly, resulting in rapid heat generation, which may be dangerous.

The organic solvent contained in the polymerizable composition used in the method for producing the water-soluble adhesive tape of the present invention is
Although not particularly limited, alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 3-butanol, isobutanol, t-butanol, methyl acetate, ethyl acetate, etc. Preferred are acetic acid esters of, formic acid esters such as methyl formate and ethyl formate, ketones such as acetone and 2-butanone, and hydrophilic organic solvents such as tetrahydrofuran, 1,2-dimethoxyethane, and 1,2-diethoxyethane. One or more of these are preferably used. The hydrophilic organic solvent here means an organic solvent having a solubility in water at 20 ° C. and atmospheric pressure of about 10% by weight or more.

These organic solvents uniformly mix different kinds of polymerizable monomers having different polarities contained in the polymerizable composition and improve the wettability of the polymerizable composition to the support to improve the support and the adhesive. Improves adhesion with. Further, since the heat generation during photopolymerization is suppressed by the heat storage and latent heat of vaporization, the composition ratio of the polymerizable monomer in the polymerizable composition does not change from the composition ratio at the time of charging, and a high-quality adhesive having a predetermined composition can be obtained. In addition to being obtained, expensive polymerization heat excluding equipment is unnecessary.

The phosphoric acid ester of (meth) acrylate having a terminal OH group, which is an essential component of the polymerizable composition used in the production method of the present invention, has a high polarity and is difficult to dissolve in a low polarity organic solvent. It is preferable to use the hydrophilic organic solvent as described above, and in order to effectively suppress heat generation during photopolymerization, among the hydrophilic organic solvents, those having a boiling point of about 120 ° C. or less are preferable. It is more preferable that the temperature is not higher than the boiling point of the polymerizable monomer used.

The content of the above organic solvent is not particularly limited, but it is preferably about 1 to 50 parts by weight of the organic solvent with respect to 100 parts by weight of the total amount of the polymerizable monomers. If the content of the organic solvent is less than about 1 part by weight, the effect of incorporating the organic solvent cannot be obtained. On the contrary, if it exceeds about 50 parts by weight, the polymerization rate becomes slow and the productivity may decrease.

In addition to the above-mentioned components, the polymerizable composition used in the production method of the present invention may optionally contain an alkyl mercaptan such as lauryl mercaptan or octyl mercaptan in order to control the molecular weight of the pressure-sensitive adhesive. A chain transfer agent such as a system is added in an amount of 0.
You may contain about 0 to 1 part by weight.

Furthermore, in addition to the above-mentioned components, the polymerizable composition used in the production method of the present invention may contain a copolymerizable cross-linking agent or a cross-linking agent in order to increase the molecular weight of the pressure-sensitive adhesive and increase the cohesive force, if necessary. A crosslinking agent such as a functional group reactive crosslinking agent may be contained.

The above-mentioned copolymerizable cross-linking agent means a compound having two or more unsaturated bonds in the molecule, and when copolymerized with the polymerizable monomer, the polymer is branched so that the polymers are bonded together. For example, hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, Trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy acrylate, polyester acrylate, urethane acrylate and the like can be mentioned, and one or more of these are preferably used.

The above-mentioned functional group-reactive cross-linking agent has two or more reactive points in the molecule and does not itself copolymerize, but reacts with the functional group in the polymer to form a covalent bond or an ionic group. It refers to those that form bonds and crosslink polymers.
For example, various crosslinking agents such as polyisocyanate-based, epoxy-based, amine-based, aziridine-based, metal oxide-based and organometallic complex-based crosslinking agents can be used, and one or more of these are preferably used.

The content of the above-mentioned copolymerizable cross-linking agent and / or functional group-reactive cross-linking agent is not particularly limited,
The amount of the crosslinking agent is preferably about 5 parts by weight or less based on 100 parts by weight of the total amount of the polymerizable monomers. When the content of the cross-linking agent exceeds about 5 parts by weight, the cross-linking density becomes too high, and the obtained pressure-sensitive adhesive becomes hard and the tackiness is hindered, or the water solubility becomes poor.

Furthermore, in the polymerizable composition used in the production method of the present invention, a tackifying resin, a thickener, an antioxidant, a plasticizer, a softening agent may be added, if necessary, within a range that does not impair the object of the present invention. Various additives such as an agent, an inorganic filler, a colorant, a surfactant, and a removability imparting agent may be contained.

The method for producing the water-soluble adhesive tape of the present invention comprises:
The above-mentioned polymerizable composition is directly coated on at least one surface of the support, and first, light is irradiated to photopolymerize the polymerizable monomer,
Then, it is dried by heating to volatilize the organic solvent.

The type of the support is not particularly limited, but examples thereof include polyester films, polyethylene films, polypropylene films, polystyrene films, polyacetate films, polyamide films, plastic films such as acetyl cellulose films, and copper. Foil, metal foil such as aluminum foil, laminate of plastic film and metal foil, paper, synthetic paper, non-woven fabric,
Examples include cloth, synthetic cloth, and laminates of these with plastic films, metal foils, and the like, and these are preferably used.

In the production method of the present invention, since a relatively low-viscosity polymerizable composition is directly applied to at least one side of the support, the above-mentioned porous material such as paper and cloth is used as the support. In this case, in order to prevent the polymerizable composition from penetrating, it is desirable to laminate it with a plastic film or a metal foil. The thickness of the support is not particularly limited, but generally about 10 to 200 μm is preferable. Further, in order to improve the adhesive strength with the obtained pressure-sensitive adhesive, it is desirable to subject the plastic film surface of the above-mentioned support to surface oxidation treatment such as corona treatment. Not necessarily required.

The method of applying the polymerizable composition to the support is not particularly limited, and a pre-weighing type coater such as a bottom feed reverse coater, a top feed reverse coater, a transfer roll coater, a gravure coater or a fountain die coater, and A post-weighing type coater such as an air knife coater, a Meyer bar coater or a comma coater is preferably used.

The coating thickness of the polymerizable composition on the support is not particularly limited, but the thickness of the obtained adhesive after drying is preferably about 10 to 200 μm on one side.

Photopolymerization of the polymerizable composition coated on the support
The type of light to be emitted is not particularly limited.
However, it has high energy and promptly supplies the photopolymerization initiator.
Examples include short-wavelength electromagnetic waves and electron beams that can be excited.
Ultraviolet rays, gamma rays, etc. are listed as the electromagnetic waves of short wavelength.
However, it is easy to generate and the device is compact.
In addition to being able to do so, molecular cutting and polymer hydrogen abstraction, etc.
It is preferable to use ultraviolet rays that are unlikely to cause crosslinking due to
Yes. Irradiation with UV light has an emission distribution below 400 nm.
Is preferably carried out by a lamp that has, for example, a low
Pressure mercury lamp, medium pressure mercury lamp, high pressure mercury lamp, ultra high pressure mercury lamp, ke
Mical lamp, black light lamp, microwave
A pumped mercury lamp, metal halide lamp, etc. are preferably used.
However, the wavelength distribution is sharp and the molecular weight of the adhesive is particularly high.
An ultra-high pressure mercury lamp that is easy to control the crosslinking degree is particularly preferable.
The light irradiation intensity of these lamps depends on the combination of polymerizable monomers.
Depending on the molecular weight and molecular weight distribution of the target adhesive
It may be set appropriately, but in general, the acetophenone group
When using a cleavage type photopolymerization initiator having
100 mW / cm²It is preferably about the same. Light irradiation
Strength is 0.1mw / cm ²Polymerization is sufficient if less than
Not getting up, on the contrary, 100 mw / cm²If the degree exceeds
There is a danger of explosion due to heat generation and runaway because it progresses rapidly
There is a chance

In the photopolymerization, the dissolved oxygen in the polymerizable composition and the oxygen in the atmosphere of the light irradiation zone inhibit the polymerization, which adversely affects the polymerization rate, molecular weight, molecular weight distribution, etc. of the obtained adhesive. Therefore, an inert gas such as nitrogen gas may be blown into the polymerizable composition and the light irradiation zone in advance to substitute oxygen, and the oxygen concentration should be suppressed to about 5000 ppm or less, more preferably about 1000 ppm or less. Is desirable. Furthermore, the polymerizable composition applied to the support is coated with a release-treated surface of a light-transmitting release film such as a polyester film subjected to a release treatment, and photopolymerization is carried out with oxygen. It is an effective way to block.

In the production method of the present invention, it is necessary to remove the organic solvent in the adhesive by heating and drying as soon as possible after the photopolymerization of the polymerizable composition is completed. When the organic solvent remains, the cohesive force of the pressure-sensitive adhesive may be lowered, the shear strength and heat resistance may be lowered, and the adhesive may be bleeded to the surface of the pressure-sensitive adhesive to impair the adhesion to the adherend. Heat drying of the organic solvent, for example, using a semi-enclosed oven that can remove the solvent vapor out of the system, the temperature preset in consideration of the boiling point of the solvent and the heat resistance of the support, air volume, time Etc. may be performed by a conventional method.

The water-soluble pressure-sensitive adhesive tape according to the production method of the present invention has a pressure-sensitive adhesive layer obtained by photopolymerizing a polymerizable composition coated on at least one surface of a support and then drying by heating, for example, release paper. It is commercialized by laminating the release treated surface of a release material such as or a release film and winding it.

[0041]

The method for producing the water-soluble pressure-sensitive adhesive tape of the present invention comprises preliminarily neutralizing an acid group in a polymerizable monomer containing a phosphate ester of (meth) acrylate having a terminal OH group as an essential component with an alkaline neutralizing agent, Since the pressure-sensitive adhesive obtained by heating and drying after photopolymerization is used, the water-soluble pressure-sensitive adhesive tape obtained is
It exhibits excellent solubility in acidic water, neutral water and alkaline water.

Further, since the polymerizable composition contains an organic solvent, heat generation during photopolymerization is suppressed, so that the composition ratio of the polymerizable monomer does not change from the composition ratio at the time of charging, and the obtained pressure-sensitive adhesive is obtained. Is of high quality with a given composition and does not require expensive polymerization heat rejection equipment.

[0043]

EXAMPLES In order to explain the present invention in more detail, examples will be given below. In addition, "part" in an Example means a "weight part."

(Example 1)

(A ) Preparation of Polymerizable Composition In a container equipped with a thermometer, a stirrer and a nitrogen introducing tube, 75 parts of an ester of 2-hydroxyethyl acrylate and phosphoric acid “light ester PA” (manufactured by Kyoeisha Yushi Co., Ltd.), 25 parts of butyl acrylate, 100 mol% of triethanolamine as an alkaline neutralizing agent, 30 parts of ethanol and a photopolymerization initiator "Darocur 1173" (α-hydroxy-α,
α'-Dimethylacetophenone, manufactured by Merck) 0.96
A portion was charged, and the mixture was stirred and mixed for 20 minutes while blowing nitrogen gas at a rate of 2 liters / minute to prepare a polymerizable composition.

( B) Preparation of pressure-sensitive adhesive tape The polymerizable composition was release-treated to have a thickness of 38 μm.
PET film (manufactured by Lintec Co., Ltd., hereinafter, release treatment P
ET) and the surface tension is 54 dyn /
The corona-treated surface of a PET film with a thickness of 38 μm (hereinafter referred to as corona-treated PET) that has been corona-treated to have a thickness of 100 μm has a thickness of 100 μm after polymerization and drying.
applied so that the dissolved oxygen amount is about 1000 p in advance.
In an oven adjusted to pm, a low pressure mercury lamp was used to irradiate ultraviolet rays having a central wavelength of 200 nm to perform photopolymerization. At this time, the maximum light irradiation intensity is 15 mW /
adjusted to cm ^2, and irradiation time was 90 consecutive seconds. Then, it was dried in a semi-closed oven at 110 ° C. for 10 minutes, and the organic solvent was volatilized to prepare two types of adhesive tapes.

( C) Evaluation The performance of the obtained polymerizable composition, pressure-sensitive adhesive and pressure-sensitive adhesive tape was evaluated by the following method, and the results are shown in Table 1. The evaluation is 23 ° C.-65% RH unless otherwise specified.
I went under the atmosphere.

Liquid temperature rise : A rod-shaped thermometer was inserted into the polymerizable composition coated on the corona-treated PET to measure the exothermic temperature (A) during photopolymerization. As a comparative control, the same procedure was performed for a polymerizable composition containing no photopolymerization initiator to measure the exothermic temperature (B) during polymerization.
Was defined as the liquid temperature rise (° C).

State of coated surface: The state of the coated surface such as the presence or absence of foaming during photopolymerization of the polymerizable composition coated on the corona-treated PET was visually observed.

Polymerization rate : The amount of residual monomer of the photopolymerized pressure-sensitive adhesive was measured by FID gas chromatography, and the polymerization rate (%) was determined by the following equation.

[0051]

[Equation 1]

Acid value change : The acid value of the produced polymer (adhesive) was measured according to JIS K-5903 "ester gum", and the difference from the theoretical acid value depending on the composition ratio of the charged monomers was calculated by the following formula. And acid value change (mgKOH / g). The composition variation of the charged monomer is mainly due to the volatilization of low boiling point monomers other than the phosphoric acid ester of (meth) acrylate having a terminal OH group. Therefore, it can be said that the lower the acid value change degree, the less the composition variation of the charged monomer. . Acid value change (mgKOH / g) =
Acid value of polymer-acid value of charged monomer

Solubility : An adhesive tape having a release-treated PET cut into 50 mm square as a support was treated with 60 ° C. alkaline water (1N potassium hydroxide aqueous solution, pH 13.8).
The weight loss rate (%) of only the adhesive after immersion in 300 cc and standing for 1 hour was measured. In addition, the same test was conducted with 60 ° C. neutral water (1N sodium chloride aqueous solution, pH 6.8).
And 60 ° C. acidic water (3N aqueous sulfuric acid solution, pH 0.
I also went to 2).

(Examples 2 to 7)

A polymerizable composition was prepared in the same manner as in Example 1 with the composition shown in Table 1. Then, in the same manner as in Example 1, two types of adhesive tapes were produced.

The performance of the resulting polymerizable composition, pressure-sensitive adhesive and pressure-sensitive adhesive tape was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

(Comparative Examples 1 to 4)

A polymerizable composition was prepared in the same manner as in Example 1 with the composition shown in Table 2. Then, in the same manner as in Example 1, two types of adhesive tapes were produced.

The performance of the resulting polymerizable composition, pressure-sensitive adhesive and pressure-sensitive adhesive tape was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[0060]

[Table 1]

[0061]

[Table 2]

As shown in Table 1, the polymerizable compositions of Examples 1 to 7 used in the production method of the present invention showed a small rise in the liquid temperature during photopolymerization and had a good coated surface condition. . or,
The obtained pressure-sensitive adhesive has a high polymerization rate, little variation in the composition of the charged monomers, and exhibits excellent solubility in any of acidic water, neutral water and alkaline water. On the other hand, as shown in Table 2, the polymerizable compositions of Comparative Example 1 and Comparative Example 4 containing no organic solvent had a large degree of increase in liquid temperature during photopolymerization, and thus caused a large amount of foaming and the state of the coated surface. In addition, the acid value change is large and the composition of the charged monomers varies widely. Further, the pressure-sensitive adhesives obtained from the polymerizable compositions of Comparative Examples 2 and 3 containing no alkaline neutralizing agent have excellent solubility in alkaline water, but poor solubility in acidic water and neutral water. .

[0063]

Industrial Applicability As described above, according to the production method of the present invention, a water-soluble adhesive having excellent solubility in acidic water, neutral water and alkaline water and having high-quality adhesive properties. You can get a tape. Further, the production method of the present invention does not require expensive polymerization heat elimination equipment.

Claims (1)

[Claims] 1. A support comprising a polymerizable composition containing a polymerizable monomer having a phosphate ester of (meth) acrylate having a terminal OH group as an essential component, an alkaline neutralizing agent, a photopolymerization initiator and an organic solvent. A method for producing a water-soluble pressure-sensitive adhesive tape, which comprises coating on at least one side, photopolymerizing, and then heating and drying.