JPS60179484A - Energetic ray-curable pressure-sensitive adhesive composition - Google Patents

Abstract

PURPOSE:To provide the titled adhesive compsn. which has a high curating rate and can be cured even in an oxygen-contg. atmosphere, consisting of a (co)polymer of a (meth)acrylic monomer. CONSTITUTION:An adhesive compsn. contains a polymer of a (meth)acrylic monomer of the formula (wherein R1 is H, methyl; R2 is a 1-4C alkylene; R3 is a 1-4C alkyl; n is 1-4) such as methoxyethyl acrylate or a copolymer (having a glass transition point of -10 deg.C or below) of said monomer with other monomer such as n-butyl acrylate as a main component and optionally additives such as tackifier, filler, softening agent, etc. The compsn. can be cured by the irradiation of ultraviolet rays, electron beam or gamma-rays. However, it is necessary to add 0.001-10wt% photopolymerization initiator when ultraviolet rays are used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to the treatment of hard materials by irradiation with active energy rays.
The present invention relates to a pressure-sensitive adhesive composition having excellent physical properties.

Conventionally, rubber-based or acrylic thread polymers have been used as pressure-sensitive adhesives, but mere thermoplastic polymers lack cohesive strength. Therefore, in the case of acrylic materials, functional groups were introduced for crosslinking, a crosslinking agent was added, and heat curing was performed. However, it consumes a lot of time and energy. In order to improve these drawbacks, active energy ray-curable pressure-sensitive adhesives have recently been studied.

The active energy ray-curable pressure-sensitive adhesive used in this rod is an acrylic wholesaler S1, which has at least 21 unsaturated double bonds in its molecule that is reactive to active energy rays, or an acrylic oligomer. It is known that it is blended with a type of complex.

However, acrylic monomers or acrylic oligomers have a problem of odor pollution due to their unique odor, in addition to the problem of rashes when they adhere to the skin.

Even on the platform for curing, the reaction was slow in air, and long irradiation was required. Furthermore, the physical properties of the pressure-sensitive adhesive after curing, such as adhesive strength, are not necessarily equal to i'ii4 plus i4j.

In view of the above-mentioned conventional problems, the present inventors have earnestly endeavored to improve
As a result, the use of acrylic yarn monoliths or acrylic oligomers, which had been a problem in the past, was avoided by using 1f polymers of unique (meth)acrylic monomers as an essential component. We have now obtained an active energy-curing pressure-sensitive bonding agent composition that cures quickly and provides a pressure-sensitive adhesive with excellent performance even without the use of active energy.

That is, the present invention provides (meta) represented by the following general formula (A)
The acrylic monomer IF polymer is an active energy curing pressure sensitive adhesive composition comprising a copolymer of the above monomer and a monomer copolymerizable therewith.

l too.

CH*=OO-0+R* ova,...[A]1 However, R1 is hydrogen or a methyl group, R is an alkylene group having 1 to 4 carbon atoms, Rs is an alkyl group having 1 to 4 carbon atoms, and R is an alkyl group having 1 to 4 carbon atoms. It is an integer from 1 to 4. Represented by the above general formula (A) (
In meth)acrylic monomers, kanro has 1 to 4 carbon atoms.
The alkylene group may be either linear or branched, and although 釠 and is an alkyl group having 1 to 4 carbon atoms, it may also be linear or branched.

Compared to conventional products, the composition of the present invention cures well even in an atmosphere containing oxygen, and has the predictable and impressive effect of significantly improving the adhesive strength and/or cohesive strength of the resulting pressure-sensitive adhesive. It shows.

To explain each component constituting the composition of the present invention,
The (meth)acrylic compound represented by i in the above general formula (A) is an essential monomer, and examples of the monomer include methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, and butoxyethyl (meth)acrylate. Ethyl (meth)acrylate, methoxyethoxyethyl (meth)acrylate, ethyl carpitol (meth)acrylate, methyl triglycol (meth)acrylate, 1-ptoxyglobil (meth)acrylate, 3-methoxybutyl (meth)acrylate, 1-ethoxy Examples include butyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, methoxymethyl (meth)acrylate, 3-ethoxy-propyl (meth)acrylate, and ethoxymethyl (meth)acrylate. Among these monomers, R,
is hydrogen, bird is a linear or branched alkylene group having 1 to 4 carbon atoms, 1 is an alkyl group having 1 to 2 carbon atoms, and n is 1 for ease of production and availability. preferred.

Examples of the monomer 111 are methoxyethyl acrylate, ethoxyethyl acrylate, 1-ethoxybutyl acrylate, 3-methoxypropyl acrylate, methoxymethyl acrylate, 3-ethoxypropyl acrylate, and ethoxymethyl acrylate. Examples of monomers copolymerizable with the (meth)acrylic monomer represented by the general formula [A] include methyl (meth)acrylate, ethyl (meth)acrylate, pucinometh)acrylate, and isobutyl (meth)acrylate. Acrylic or methacrylic alkyl esters such as acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, (meth)acrylic acid, 2-hydroxyl group meth)acrylate, 3-
Vinyl yarn monomers containing side chain functional groups such as hydroxypropyl (meth)acrylate, glycidyl (meth)acrylate, N-methylol (meth)acrylamide, N-butoxymethyl (meth)acrylamide, vinyl acetate, acrylonitrile, styrene, maleic anhydride Examples include acids. Among these monomers, alkyl acrylates having 2 to 8 carbon atoms are suitable for pressure-sensitive adhesives. Furthermore, when used as a removable adhesive to improve adhesive strength and solvent resistance or to cure using a crosslinking agent, carboxyl groups, hydroxyl groups, amide groups,
It is preferable to use a monomer having a glycidyl group in combination.

The proportion of the monomer used is determined so as not to impair adhesiveness.
It is determined by the glass transition point (Tg point) of the polymer.

The general Tg point for pressure sensitive adhesives is -1.
, 0°C or lower, and more preferably -30°C or lower. Tg point is -10”C-tEfi
If the Tg point of a polymer is exceeded, the composition will have poor tack and will become a pressure-sensitive adhesive, which is not desirable. There is a method of measuring and finding the Tg point as the intersection of two straight lines with different slopes on the specific volume-temperature curve.

However, simply because the Tg point value of each single polymer is known, the Tg point of the copolymer can be calculated using the following calculation formula (A, V, Tobols
kyi”Propertics and 5truct
ure of Polymers” John Wi I
ey & 5ons+ Inc., New York (
'60)) CI=weight fraction C of component 1: weight fraction Tg of component 2, : glass transition point of component 1 sole polymer (0K)
Tg, : Glass transition temperature of component 2 sole polymer ('K
) Tg, : Glass transition point of component 1 sole polymer (0K)
Tg: Components 1, 2. ...Glass transition point (°K) of the co-1fi coalescence polymer of Tada, where C1+0 snow+...-left Q, = l.

Although a crosslinking reaction may occur depending on the composition of the polymer, it is generally assumed that no crosslinking reaction occurs.

For typical monomers, the Tg points of their single polymers are as follows.

Single polymer> (Tg point) Polymethyl acrylate 8°C Polymethyl methacrylate 105°C Polyethyl acrylate -23°C Poly n-butyl acrylate -54°C 4°C Polymer butyl acrylate -24°G To poly 2-ethyl Xyl acrylate -85°C Polyacrylic acid 106°C Polymethacrylic acid 144°C Polystyrene 100'C Polyvinyl acetate 30'C Polyacrylonitrile 96°C Polyhydroxyethyl methacrylate 55°C Polyacrylamide 165°C 3-methoxybutyl acrylate -56°C 2-methoxy Ethyl acrylate - 50°C 2-ethoxyethyl acrylate - 50'C3-methoxypropyl acrylate - 75°C 3-ethoxyethyl acrylate -5
5°C The sound used in the monomer mixture of the general formula (A) used in the present invention is inseparably linked to the curability with active energy rays, and must be at least 3%
It is preferable that the above is l.

It is more preferable that the average temperature is at least 100%. If it is less than 3, the curability with active energy rays is poor and a good pressure-sensitive adhesive cannot be obtained.

The copolymer or homopolymer of the present invention can be synthesized by conventional polymerization methods such as bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization.

The polymer obtained as described above exhibits active energy ray curability, but if necessary, a tackifier may be added to the polymer.
Fillers, pigments, softeners, etc. can be added. In addition, sensitization can be achieved by crosslinking by various methods such as isocyanate crosslinking using carboxyl groups and hydroxyl groups introduced into the co-monomer, melamine crosslinking, amine crosslinking using glycidyl groups, acid crosslinking, and metal crosslinking using carboxyl groups. It may also be a pressure adhesive composition.

Curing in the present invention is carried out by irradiation with active energy rays. The active energy rays used in the present invention refer to electric radiation such as ultraviolet rays, electron beams, and γ rays.

The composition of the invention can be applied to ultraviolet light, frost, l1i11. Although it is cured by the action of sexual radiation, it may contain a curing accelerator to further accelerate curing, and in many cases this is preferable.

If the curing means is ultraviolet light, conventional photoinitiators are used. Preferred photoinitiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, penzoin isobutyl ether, benzoin octyl ether, benzyl, diacetyl,
Methylxanthone, 2,4-dimethylthioxanthone,
Thioxanthone compounds such as 2,4-diethylthioxanthone and 2,4-diisopropylthioxanthone, sulfur compounds such as diphenyl disulfide and dithiocarbamate, naphthalene compounds such as 2-chloromethylnaphthalene, anthracene, iron chloride, etc. Photoinitiators that can be used particularly preferably include benzophenone, benzophenone compounds such as 3,3'-dimethyl-4-methoxybenzophenone, 2-chlorothioxanthone, 2,4
Examples include thioxanthone compounds such as -dimethylthioxanthone, 2,4-diethylthioxanthone, and 2,4-dipropylthioxanthone.

When the curing means is ionizing radiation such as electron beams or gamma rays, it cures quickly without using an initiator.
There is no particular need to use an initiator.

The amount of the photoinitiator to be used is preferably 0.0% based on the composition.
001-1Qwt%, more preferably 0.01-5w
It is in the range of t%.

The active energy ray-curable pressure-sensitive adhesive composition of the present invention is rapidly cured by active energy rays without consuming a large amount of time and energy, and has excellent adhesive strength, holding power,
Adhesive tapes with excellent tack properties can be easily obtained and are industrially useful. Since it can be cured without using acrylic oligomer, it can prevent rashes caused by it.
There is no odor problem.

The present invention will be explained in more detail with reference to Examples and Comparative Examples below. In the examples, parts refer to parts by weight, and adhesive strength, holding power, and tack were measured by the following methods.

(1) Method for making an adhesive sheet After the pressure-sensitive adhesive coated on one side of a 25μ polyester film was made to have a thickness of about 30μ, active energy rays were irradiated from the top of the pressure-sensitive adhesive, After combining the release paper or combining the release papers, a pressure-sensitive adhesive sheet was prepared by irradiating active energy rays from the polyester film surface or without irradiating the polyester film.

(2) Adhesive force The adhesive force of the adhesive sheet prepared as above was measured by JI8.
It was attached to a stainless steel plate using ZO237 (adhesive tape, adhesive sheet testing method), and after 30 minutes, it was peeled off at 180 degrees and the adhesive strength was measured.

(3) B: Measurement of holding force was also carried out by pasting a 25 x 25 mm piece on a stainless steel plate using JI8ZO237, and after 30 minutes at 80°C.
ky load and if the test piece does not fall from the stainless steel plate or within 60 minutes,
The distance deviated at that time was measured.

(4) Measurement of tack tack was also performed using JI8ZO237 to measure the maximum ball number of a ball that stopped at an inclination angle of 30 degrees using the ball rolling method.

Example 1 A four-bottle flask equipped with a stirrer, a thermometer, a dropping funnel, and a nitrogen gas blower. Ioo parts of a monomer mixture consisting of 55 parts of gn-butyl acrylate, 40 parts of 3-methoxybutyl acrylate, and 5 parts of acrylic acid. 2 of them
0 parts and 80 parts of ethyl acetate, heated to 70°C while stirring in a nitrogen stream, and started the reaction by adding a solution of 0.3 parts of a1α'-azobisisobutyronitrile dissolved in 10 parts of ethyl acetate. and add the remaining 80% of the monomer mixture to this.
A mixture of 50 parts of ethyl acetate and 0.5 parts of α,a'-azobisisobutyronitrile was continuously added dropwise over a period of 4 hours.
A solution of 0.2 parts of α'-azobisinbutyronitrile dissolved in 10 parts of ethyl acetate was added dropwise, and stirring was continued for 2 hours at the same temperature to obtain a polymer solution, that is, an active energy ray-curable pressure-sensitive adhesive. I was able to obtain the composition. The Tg of the polymer is -50
It was ℃.

Regarding this composition, 2.
The adhesive strength of the adhesive sheet obtained by irradiating the electron beam at a dose of 4 megarads was 920.9 f/25 mm, the holding strength was consistent for 60 minutes, and the tack was 9.7Q) Comparative Example 1 The adhesive strength of the adhesive sheet obtained using the activated energy ray-curable pressure-sensitive adhesive composition without irradiation with electron beam was 1.80 oyr / 25 m, and the holding power was 2.
It fell in minutes.

Example 2 0.2wt of benzophenone was added to the active energy ray-curable pressure-sensitive adhesive composition obtained in Example 1 as a photoinitiator.
% of the composition was exposed to ultraviolet light at a distance of 15 cm from the polyester film surface using a high-pressure mercury lamp [Ushio Electric UniCure System UV4000 ozone-less type semi-concentrating '511 lamp] with an output of 80 W/cm. The adhesive strength of the adhesive sheet obtained by irradiating for 10 seconds is 9
80 gf/25 mm, the holding force was 60 minutes without any deviation, and the tack was 9.

Example 3 The adhesive strength of a pressure-sensitive adhesive sheet 89 ('l#f/ The holding power for 25 m was 60 minutes without any deviation, and the tank was 8.

Example 4 In Example 1, each monosole contains 40 parts of 2-ethoxyethyl acrylate, 1-20 parts of 3-ethoxypropyl acrylate, and 2 parts of ethyl acrylate.
An active energy ray-curable pressure-sensitive adhesive composition was obtained by polymerizing a metabolite mixture consisting of 0 parts pyrol acetate, 15 parts 2-hydroxyethyl methacrylate, and 5 parts. The Tg of 3 < coalescence was -33°C. Table 1 also shows the adhesive strength, holding power, and tack of the pressure-sensitive adhesive sheet obtained in the same manner as in Example 1.

Example 5 A monomer mixture in which each monomer in Example IK was 3 parts of 3-methoxypropyl acrylate, 92 parts of iso-butyl acrylate, and 5 parts of glycidyl methacrylate was polymerized to form a #Kinhon-odor active energy ray-curable type. A pressure sensitive adhesive composition was obtained. The Tg of the coalition is
It was -24°C. Table 1 also shows the adhesive strength, holding power, and tack of the adhesive sheet obtained in the same manner as in Example 1.

Example 6 An active energy ray-curable pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except for Group 1, in which the monomer was 100 parts of 2-methoxyethyl acrylate. The 'rg of the polymer is -5
It was 0°C. Table 1 also shows the adhesive strength, holding power, and tack of the adhesive sheet obtained in the same manner as in Example 1.

Example 7 A monomer mixture in which each monomer in Example 1 was 35 parts of 2-ethoxyethyl acrylate and 65 parts of n-butyl methacrylate was polymerized to obtain an active energy ray-curable pressure-sensitive adhesive composition. Ta. The 'rg of the polymer is -12℃
Met. Also, Example 1. Table 1 shows the adhesive strength, holding power, and tack of the adhesive sheet prepared in the same manner.

Example 8 A monomer mixture in which each monomer in Example 1 was 10 parts of 3-methoxypolar acrylate, 80 parts of 2-ethylhexyl acrylate, 7 parts of acrylonitrile, and 3 parts of methacrylic acid was polymerized and cured with active energy rays. A type pressure sensitive adhesive composition was obtained. The Tg of the polymer was -72°C. Table 1 also shows the adhesive strength, holding power, and tank strength of the adhesive sheet obtained in the same manner as in Example 1.

Comparative Example 2 A pressure-sensitive adhesive composition was obtained by polymerizing the monomer mixture in Example 1, in which each monomer consisted of 95 parts of n-butyl acrylate and 5 parts of acrylic acid. The Tg of the polymer was -49°C. Table 1 shows the adhesive strength, holding power, and warp of a pressure-sensitive adhesive sheet obtained by irradiating this composition with an electron beam in the same manner as in Example 1.

Example 9 In Example 5, electron beam irradiation #j! Table 1 shows the adhesive strength, holding power, and tack of the adhesive sheet obtained in the same manner as in Example 5, except that the amount was changed to 5.0 Megaland.

Example 10 In Example 6, electron beam irradiation ifMffi was 1.2
Table 1 shows the adhesive strength, holding power, and tank strength of the adhesive sheet obtained in the same manner as in Example 6 except that Megaland was used.

Example 1 The adhesive strength of a pressure-sensitive adhesive sheet obtained in the same manner as in Example 2 except that 2-chlorothioxanthone was used as the photoinitiator and the ultraviolet irradiation time was 5 seconds. The holding power and tack are shown in Table 2.

Table 1 Example 12 Adhesive strength of a pressure-sensitive adhesive sheet obtained in the same manner as in Example 2, except that benzyl dimethyl ketal was used as the photoinitiator and the ultraviolet irradiation time was 15 seconds. The holding power and tack are shown in Table 2.

Example 13 Adhesive strength and retention of a sticky sheet obtained in the same manner as in Example 2 except that benzoin isobutyl ether was used as the photoinitiator and the ultraviolet irradiation time was changed to 20 seconds. The force and tack are shown in Table 2.

Example Work 4 In Example 2, light υ? The J initiator was 2,4-dimethylthioxant/, and the amount added was 0.05 wt%;
Table 2 shows the adhesive brim retention and Ir brim tack of the pressure-sensitive adhesive sheet obtained in the same manner as in Example 2 except that the irradiation time of ultraviolet rays was 5 seconds.

Example 15 In Example 2, the amount of photoinitiator added was 0.05wt.
Table 2 shows the adhesive strength and tack of the adhesive sheet obtained in the same manner as in Example 2, except that the UV irradiation time was 5 seconds.

Example 16 0.5 wt % of Coronet) L (polyisocyanate cross-linking agent manufactured by Nippon Polyurethane Industries @) was added as a cross-linking agent to the active energy ray-curable pressure-sensitive adhesive composition obtained in Example 1.
A composition containing 0.05 wt% of benzophenone as a photoinitiator was coated on one side of a 25 μm polyester film, and after the pressure-sensitive adhesive was made to have a thickness of about 30 μm, a release paper was attached. Storage 17 in a state where it is not irradiated with active energy rays, and after crosslinking the polyisocyanate, the adhesive strength and holding power of the adhesive sheet obtained by irradiating the polyester film surface with ultraviolet rays for 5 seconds in the same manner as in Example 2,
The tack is shown in Table 2.

Comparative Example 3 In Example 16, the adhesive strength, holding power, and tack of the adhesive sheet before irradiation with ultraviolet rays are shown in Table 2.

Example 17 In Comparative Example 3, the polyester surface of the adhesive sheet attached to a stainless steel plate was irradiated with ultraviolet rays for 5 seconds to measure adhesive strength and retention strength, and the adhesive strength and retention strength after 180 degree peeling are shown in Table 2. Ta.

May 20, 1980, before the procedural amendments Kazuto Wakasugi, Commissioner of the Patent Office 1. Indication of the case: 1982 Patent Application No. 34243υ 2. Name of the invention: Active energy ray-curable pressure-sensitive adhesive composition 3. Amendments made. Patent applicant address: 1-14-1-5 Nishi-Shinbashi, Minato-ku, Tokyo Contents of amendment (1) On page 5, line 8 of the specification box, the phrase “carbon number 1-2” was replaced with “carbon number 1-2” The number of carbon atoms is 1 to 4.”

(2) Add "butoxyethyl acrylate-1" between "acrylate" and "J, etc." on page G, line I of the specification section.

(3) rci between the 3rd and 4th lines from the bottom of the 7th line
:Add 1 share of component i.

Claims (1)

[Claims] 1. A homopolymer of a (meth)acrylic monomer represented by the following general formula [A] or a copolymer of the monomer and a monomer copolymerizable therewith. An active energy ray-curable pressure-sensitive adhesive composition. 1 However, R1 is hydrogen or a methyl group, R2 is an alkylene group having 1 to 4 carbon atoms, R3 is an alkyl group having 1 to 4 carbon atoms, and n
is an integer from 1 to 4.