JPS63135470A - Actinic radiation-curable, pressure-sensitive adhesive composition - Google Patents

Abstract

PURPOSE:To form a compsn. which has excellent trackiness and can be easily cured by an actinic radiation, by blending a polyalkylene glycol monoalkyl ether mono(meth)acrylate with a specified monofunctional acrylate and other monofunctional (meth)acrylate. CONSTITUTION:An actinic radiation-curable, pressure-sensitive adhesive compsn. is formed from 10-40wt% component A, 5-40wt% component B and 20-85wt% component C. [A]: at least one member of polyalkylene glycol monoalkyl ether mono(meth)acrylates of formula I (wherein R1 is H or methyl; R2 is a 2-3C alkylene; R3 is a 4-9C alkyl; n is 1-3), [B]: at least one member of monofunctional acrylates of formula II [wherein X is a group of formula III (wherein m is 2-7; l is 1-7) or IV (wherein R4 is H or methyl; Y is a residue of a dibasic acid)] and [C]: at least one monofunctional (meth)acrylate having an MW of 200-1,000 other than the components A and B.

Description

Detailed Description of the Invention (a) Purpose of the Invention (Industrial Field of Application)
Cured by irradiation with active energy rays such as B),
The object of the present invention is to provide a composition that provides a pressure-sensitive adhesive with excellent physical properties and is non-polluting and does not essentially require the use of a solvent.

In this specification, acrylic acid and/or methacrylic acid is referred to as (meth)acrylic acid, and acrylate and/or methacrylate is referred to as (meth)acrylate.

<Prior art> Conventionally, adhesives have been used in the form of solutions of rubber-based or acrylic-based polymers dissolved in organic solvents such as toluene, xylene, and ethyl acetate, and the use of these solvents has caused various problems. Ta. That is, there are problems such as toxicity to workers, risk of fire, environmental pollution, drying speed, and waste of resources (solvent).

In order to improve these drawbacks, in recent years, adhesives using active energy rays as a curing means have been studied.

This type of active energy ray-curable adhesive is made by dissolving an acrylic polymer in a low-boiling point acrylic monomer such as butyl acrylate or 2-ethylhexyl acrylate, and is different from conventional solution-based adhesives. We were able to improve some of the problems. However, the acrylic monomer used as a diluent has a low boiling point and has a unique odor, creating new problems. That is, a deodorizing device or the like is required to avoid odor pollution. Furthermore, the physical properties as an adhesive, such as adhesive strength, were not necessarily satisfactory.

The present invention provides a novel composition that essentially does not contain a solvent or a low-boiling acrylic monomer, and is cured by irradiation with active energy rays such as UV or EB, and exhibits adhesive properties. This significantly improves the physical properties of adhesives, eliminating various problems associated with conventional technologies, such as toxicity to workers, risk of fire, environmental pollution, odor control, drying speed, and waste of resources (solvent). It is something to do.

(B) Structure of the invention <Means for solving the problem> As a result of intensive research, the present inventors have found the following prisoner, turtle and ■
Consisting of ingredients, 10 to 40% by weight of ingredients, ■]
Component 5-40 A solvent-free composition comprising 20 to 85 percent by weight of an odor component is UV. By irradiating active energy rays such as EB, a cured product with excellent physical properties as an adhesive such as adhesive strength and holding power can be formed, and various problems in conventional solvent-based adhesive compositions can be reduced. We found that improvements can be made.

Ingredients (6) and [, which are the fourth components of the present invention, will be explained below.

<Ingredients> The ingredients are polyalkylene glycol monoalkyl ether mono(meth)acrylates represented by the following formula.

In the above formula, R8 represents hydrogen or a methyl group, R2 represents an alkylene group having 2 to 5 carbon atoms, R8 represents an alkyl group having 4 to 9 carbon atoms, and n is 1 to 3. Specific examples of ingredients include ethylene glycol motubutyl ether mono(meth)acrylate, diethylene glycol mono-2
- ethylhexyl ether mono(meth)acrylate,
Examples include diglopylene glycol monohexyl ether mono(meth)acrylate, ethylene glycol monononyl ether mono(meth)acrylate, etc., and they may be blended singly or as a mixture of two or more. This component is 10 to 10, based on the total of component, (6) and mouth.
The amount should be 40% by weight, and the preferred amount is 15 to 35% by weight. If the amount is less than 10% by weight, the adhesiveness (hereinafter referred to as tack) as an adhesive will decrease, and if it exceeds 40% by weight, the adhesive strength will be significantly decreased.

R8 in the formula is suitably an alkyl group having 4 to 9 carbon atoms; if it is less than 4, sufficient strength cannot be obtained, and if it is 10 or more, it is (meta)
In addition to being difficult to handle as the acrylate becomes solid, it is also difficult to obtain sufficient tack due to increased lipophilicity. Also, from the glass transition temperature (Tg) of the cured product, the number of carbon atoms is 4 to 9.
is suitable.

In the formula, n is preferably 1 to 5; when n = Q, the vapor pressure is high and the odor is severe, causing problems in the working environment;
If is 1 or more, no environmental measures are required. Furthermore, if n is 4 or more, the tack will decrease, which is not preferable. Considering the Tg of the cured product, n is preferably 1 to 3.

Component (6)> Component (6) is a monofunctional acrylate represented by the following formula.

CH2=CH-C-0-X-H In the formula, X is a divalent group represented by the following 1) or 2),
These monofunctional acrylates may be used alone or in a mixture of two or more.

! = 1 to 7° The white monofunctional acrylate is, for example, a compound obtained by ring-opening addition polymerization of lactones to acrylic acid, and is
An example is shown in Publication No. 0-67446, and a specific example is "Aronix M-5300J (manufactured by Toagosei Kagaku Kogyo ■ part name, m = 5, ! = 1 to 5, average value of swamp = 1.8
).

Other examples of the above-mentioned monofunctional acrylates are addition polymers of acrylic acid, such as Aloe.

Kusu M-5+5OOJ (Toagosei Chemical Industry ■Product name m=
'l,! = 1 to 7, and the average value of the swamp = 1.4.

R4 is hydrogen or a methyl group.

Y in the above is a dibasic acid residue, which is a unit obtained by removing the carboxyl group from a dibasic acid, and specific examples of the group Y are:
There is the following group.

-CH, -1CH2-CH, -3-CH=C) (-1 This compound is an acrylate obtained by reacting, for example, a hydroxyl group-containing acrylate with a dibasic acid anhydride. Compounds listed in Table 1 of the publication, namely succinic acid monoacryloyloxyethyl ester, succinic acid monoacryloyloxyisoglobil ester, maleic acid monoacryloyloxyethyl ester, maleic acid monoacryloyloxyisoglobil ester, Hexahydrophthalic acid monoacryloyloxyethyl ester, tetrahydrophthalic acid monoacryloyloxyethyl ester, phthalic acid monoacryloyloxyethyl ester, phthalic acid monoacryloyloxyisopropyl ester, Himic acid monoacryloyloxyethyl ester, etc.

These components (6) must be contained in an amount of 5 to 40% by weight based on the total amount of components (6) and 40% by weight. When the temperature exceeds 10%, the evening temperature decreases significantly. The preferred content of component [F] is 10 to 30% by weight.

<Ingredient port> Ingredient port is monofunctional (meta) other than each component in ■ and (6).
It is an acrylate with a molecular weight of 200 to 1000. The reason for limiting the molecular weight to the range of 200 to 1000 is that if it is less than 200, the vapor pressure will be high and odor problems will occur, whereas if the molecular weight exceeds 1000, the viscosity of the composition will increase and the (meth) There are places where the curability is poor due to a decrease in the acryloyl group concentration. In terms of curing speed, the molecular weight of the component is 200 to 600.
It is more preferable that it is in the range of . In addition, the reason for limiting the formation note to monofunctional (meth)acrylates is that when difunctional or higher functional poly(meth)acrylates are used, the glass transition temperature of the cured product increases due to the crosslinking reaction of the composition, resulting in problems with tack and adhesion. This is because there is almost no force. Graves containing component C are based on the component table, (6) and the total amount of C.
20 to 8, subtracting each ingredient in the ingredient list and (6) from this
5 weight percent, preferably 35 to 75 weight percent.

Specific examples of ingredients that can be used in the present invention include:
There are monofunctional (meth)acrylates as shown below.

1) (Meth)acrylates of alkylene oxide polyadducts of phenol or alkylphenols such as ethylene oxide and propylene oxide, such as 0 polyethylene glycol monophenyl ether mono(
meth)acrylate, 0 polyethylene glycol monononyl phenyl ether mono(meth)acrylate, 0 polypropylene glycol monononyl phenyl ether mono(meth)acrylate.

2) (Meth)acrylates obtained from the reaction of monoepoxide and (meth)acrylic acid, such as o2-hydroxy-3-butoxypropyl (meth)acrylate, 02-hydroxy-6-hexyloxybrobyl (meth)acrylate, 02 -Hydroxy-3-phenoxypropyl (meth)acrylate.

3) A (meth)acrylate obtained by ring-opening polyaddition of a lactone to a hydroxyl group-containing (meth)acrylate, such as a 6-hexanolide polyadduct of 02-hydroxyethyl (meth)acrylate.

4) (meth)acrylates of other monofunctional alcohols, such as 0 dicyclopentenyloxyethyl (meth)acrylate, 0 tetrahydrofurfuryloxyethyl (meth)acrylate ((meth)acrylate of ethylene oxide adduct of tetrahydrofurfuryl alcohol), (meth)acrylate of 6-hexanolide polyadduct of tetrahydrofurfuryl alcohol.

<Curing of Composition> The composition of the present invention is cured by irradiation with active energy rays. In the present invention, active energy rays include UV,
In addition to EB, ionizing radiation such as Kr rays is also included, and the irradiation conditions may be according to conventional methods.

The composition of the present invention is cured by the action of UV, EB, etc.
A curing accelerator may be included to further accelerate curing.

When the curing means is UV, a photoinitiator is used, and examples of initiators that are preferably used include benzoin compounds such as benzoin, benzoin ethyl ether, benzoin methyl ether, and penzoin inglobil ether; benzyl diacetyl; , carbonyl compounds such as methylanthraquinone, acetophenone and benzophenone, sulfur compounds such as diphenyl disulfide and dithiocarbamate, naphthalene compounds such as α-chloromethylnaphthalene,
Examples include metal salts such as anthracene and iron chloride. The amount of the initiator used is preferably in the range of 0.01 to 20% by weight, preferably 0.1 to 10% by weight, based on the composition.

When the curing means is ionizing radiation such as EB or rMA, there is no particular need to use an initiator.

Storage Stabilizer> In order to prevent the composition of the present invention from gelling during storage and increase storage stability, it is preferable to use a small amount of a stabilizer. Suitable stabilizers include, for example, phenols such as hydroquinone, hydroquinone monomethyl ether, t-butylhydroquinone, catechol, and t-butylcatechol, quinones such as benzoquinone, naphthoquinone, and diphenylbenzoquinone, phenothiazine, and copper salts. The amount of these stabilizers used is o, o
The range is preferably from ooi to 0.3 weight percent.

Other Components> Although the composition of the present invention essentially does not require a solvent, there is no problem with the use of a solvent.

Ketones such as methyl ethyl ketone and methyl imbutyl ketone, acetate esters such as ethyl acetate and butyl acetate, aromatic hydrocarbons such as benzene, toluene, and xylene, etc.
It is also possible to use the composition of the present invention after diluting it with a commonly used organic solvent.

It is also possible to add soluble polymers and copolymers to the composition of the present invention to the extent that they can be dissolved; examples thereof include (meth)acrylic esters, styrene, vinyl acetate, ( monomers such as meth)acrylic acid, etc.
Examples include polymers and copolymers.

In addition, the compositions of the present invention may also contain conventional additives such as leveling agents, defoamers, tackifier flow inhibitors, and the like. These may be blended in accordance with conventional blending amounts.

<Examples and Comparative Examples> The present invention will be explained in more detail by showing Examples and Comparative Examples below. That is, a composition whose composition is shown in Table 1 (Example) and a composition whose composition is shown in Table 3 (Comparative Example) were respectively prepared, and each composition was coated on a polyethylene terephthalate film to a thickness of about 40 μm. The adhesive sheet was coated on a substrate and cured by irradiating with EB or UV under the following conditions to obtain a pressure-sensitive adhesive sheet.

EB heat irradiation Equipment: ESI "Electro Curtain" Acceleration voltage: 170 KV Irradiation dose: 5 Mrad Oxygen concentration in atmosphere = 100-200 ppm UV irradiation equipment: Ushio Inc. Back "Unicure 4000J La"
Bulb: 80W/cIt, ozone type High pressure mercury lamp Reflector: Concentrating type (condensing light on the conveyor) Conveyor speed: 15m/m++ Initiator = 2-hydroxy-2
- Contains 5 percent by weight of methylglobiophenone The performance of the pressure-sensitive adhesive sheet obtained above was measured by the following method, and the results are shown in Table 2 (Example) and Table 4 (Comparative Example). Obtained. In addition, the measurement of each performance is as follows.
The test was carried out indoors at a temperature of 25° C. and a humidity of 65%.

The pressure-sensitive adhesive sheet was pressure-bonded to a stainless steel plate, and a 180° peel test was conducted in accordance with JIS-6854.

Press the pressure-sensitive adhesive sheet to an aluminum plate, hold the pressure-sensitive adhesive sheet horizontally on the bottom side in an open air at 40°C, apply a load of 1 kg per square inch of the pressure-sensitive adhesive sheet, until it peels off and falls off. The time was measured. Those that did not fall off even after 3 hours were labeled as NC.

Pole tack: A pressure-sensitive adhesive sheet was attached to a slope at an angle of 30° with the adhesive coated side facing up, and measurements were made according to JIS-20237.

2nd I: 15:120Dj NC: 7 Table 4 (c) Effects of the Invention The composition of the present invention is easily cured by irradiation with active energy rays such as LIV and EB, and exhibits excellent adhesive properties. It is a composition that does not require the use of a solvent, and is used as a pressure-sensitive adhesive (pressure-sensitive adhesive).

Claims (1)

[Claims] 1. The following component [A] 10 to 40 weight percent, the following component [B] 5 to 40 weight percent, and the following component [C] 2
An active energy ray-curable pressure-sensitive adhesive composition comprising 0 to 85 weight percent. [A] One or two polyalkylene glycol monoalkyl ether mono(meth)acrylates represented by the following formula
More than a species. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (R_1 in the above formula represents hydrogen or a methyl group, R_2 represents an alkylene group with 2 to 3 carbon atoms, R_3 represents an alkyl group with 4 to 9 carbon atoms, n is 1 to 3.) [B] One or two monofunctional acrylates represented by the following formula
More than a species. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [X in the above formula is a divalent group shown in the following 1) or 2). 1) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ However, m = 2 ~ 7, l = 1 ~ 70 2) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ However, R_4 is hydrogen or a methyl group, and Y is Basic acid residue. ] [C] The molecular weight of components other than the above components [A] and [B] is 2
1 of monofunctional (meth)acrylates ranging from 00 to 1000
A species or two or more species.