JPH03239779A - Self-adhesive composition - Google Patents

Abstract

PURPOSE:To obtain a self-adhesive composition which is sensitive to actinic radiation such as electron beams or ultraviolet rays to exhibit excellent self- adhesiveness and cohesiveness by using a specified aliphatic polyester as its principal component. CONSTITUTION:100 pts.wt. aliphatic polyester that is liquid at room temperature [having repeating units of formulas I and II (wherein A is a divalent group having a hydrogenated 1,2-polybutadiene structure; B is a divalent group comprising a 2-20C aliphatic or alicyclic hydrocarbon, at least 50mol% of which has an unsaturated bond)] is mixed with 0.3-20 pts.wt. photopolymerization initiator (e.g. Irgacure 651, a product of Ciba.Geigy) to give a self-adhesive polyester composition.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a novel polyester-based adhesive that is easily sensitive to actinic radiation such as electron beams and ultraviolet rays and exhibits excellent adhesiveness and cohesion. The present invention relates to a drug composition.

[Conventional technology]

When conventionally known adhesives are classified based on their composition, they are broadly divided into those whose main component is rubber and those whose main component is poly(meth)acrylic acid alkyl ester. It has better oil resistance and weather resistance than the former adhesive, and has become increasingly popular in recent years.

(Problems to be Solved by the Invention) However, so-called acrylic adhesives containing poly(meth)acrylic acid alkyl ester as a main component,
Despite the above-mentioned excellent properties, there were the following drawbacks.

Acrylic adhesives are polymers obtained by copolymerizing a main monomer consisting of an acrylic acid alkyl ester or a methacrylic acid alkyl ester with a polar group-containing monomer consisting of acrylic acid, methacrylic acid, acrylic acid, etc. is used as the main component, and this polymer is usually subjected to crosslinking operations such as urethane crosslinking, ionic crosslinking, epoxy crosslinking, and peroxide crosslinking to improve cohesive strength. In this case, although the cohesive force is improved by the above-mentioned crosslinking operation, the adhesive force is conversely reduced, resulting in limitations in terms of its use.

In addition, regarding the above-mentioned crosslinking operation, for example, thermal crosslinking type may impair the stability of the adhesive composition, and the type of base material is restricted due to the deterioration of the adhesive base material due to heating during crosslinking. There was a problem.

The purpose of the present invention is to provide a new adhesive composition with excellent adhesiveness and cohesiveness, in order to overcome the problems of the conventional adhesives and to further develop adhesives. It is said that

[Means to solve the problem]

As a result of intensive studies to achieve the above object, the present inventors found that by using a specific aliphatic polyester as the main component, the present inventors can easily respond to actinic radiation such as electron beams and ultraviolet rays and have excellent adhesive properties. The present inventors have discovered that a novel pressure-sensitive adhesive composition can be obtained that exhibits good properties and cohesive properties, leading to the completion of the present invention.

That is, the present invention uses a component having a hydrogenated 1,2-polybutadiene structure and an aliphatic or alicyclic component having 2 to 20 carbon atoms as repeating units, and 50 moles of the aliphatic or alicyclic component described above. The present invention relates to a pressure-sensitive adhesive composition sensitive to actinic radiation, characterized in that it contains an aliphatic polyester that is liquid at room temperature and is composed of a component having an unsaturated bond of at least %.

[Structure and operation of the invention]

The aliphatic polyester that is liquid at room temperature and used as the main component in the present invention has the following general formula (1).
or (U); (A-(,-0-B)...(I)1 (A-0-C-B)-... (II)1 (In both formulas, A is hydrogenated l. A divalent group having a 2-polybutadiene structure, B is a divalent group consisting of an aliphatic or alicyclic hydrocarbon having 2 to 20 carbon atoms, of which 50 mol% or more consists of a component having an unsaturated bond. ) Those having a repeating unit represented by the following formulas are mentioned, and one or both of these formulas (I) and (II) are preferably used.

The polyester having a repeating unit represented by the general formula (I) is composed of a polybasic acid component having a hydrogenated l-2-polybutadiene structure (hereinafter referred to as the A-type basic acid component) and a polybasic acid component having a carbon number of 2 to 20. A polyol component (hereinafter referred to as
It can be obtained by carrying out an esterification reaction with B-type polyol component).

The polyester having a repeating unit represented by general formula (II) is a polyol component having a hydrogenated 1,2-polybutadiene structure (hereinafter referred to as an A-type polyol component).
and a polybasic acid component consisting of a component having an aliphatic or alicyclic hydrocarbon group having 2 to 20 carbon atoms as a molecular skeleton, and in which 50 mol% or more of the hydrocarbon group has an unsaturated bond, It can be obtained by carrying out an esterification reaction with (referred to as type B child basic acid component).

Hydrogenated A-type basic acid component and A-type polyol component having a 1,2-polybutadiene structure are produced by adding hydrogen to the unsaturated double bonds present in the molecule of 2-polybutadiene. is saturated, and the poly
It can be said to be a homologue of (1-butene), and its hydrogenation rate is usually 50% or more, preferably 80% or more. If the hydrogenation rate is too low, there will be too many crosslinking points and the adhesive will become too hard, making it difficult to balance the adhesive properties.

In addition, the molecular weight of these A-type basic acid components and A-type polyol components is usually 500 to 4.5% in number average molecular weight.
Preferably, it is in the range of 000.

If the molecular weight is too low, the adhesive becomes too hard when the hydrogenation rate is low, and it is difficult to balance the adhesive properties. Moreover, if the molecular weight is too high, the cohesive force will be insufficient.

As a commercially available type A basic acid component, Nl5SOPB (11000 (manufactured by Nippon Soda Tou)) is a hydrogenated 1,2-polybutadiene having carboxyl groups at both ends of the molecule.

In addition, commercially available A-type polyol components include Nl5SOPB G1-1000 and Identical 200 as hydrogenated l-2-polybutadiene having hydroxyl groups at both ends of the molecule.
0, same 3000 (all manufactured by Nippon Soda ■), etc.

On the other hand, a B-type polybasic acid component and a B-type polyol component are composed of a component having an aliphatic or alicyclic hydrocarbon group having 2 to 20 carbon atoms as a molecular skeleton, and 50 mol% or more of which has an unsaturated bond. The above hydrocarbon group may be linear or branched.

Type B polybasic acid components include malonic acid, succinic acid, methylsuccinic acid, adipic acid, pimelic acid, sebacic acid, 1.
12-dodecanoic acid, 1,14-tetradecanonic acid, a
-Dicarboxylic acids such as n-hexyladipic acid, tetrahydrophthalic acid, and endomethylenetetrahydrophthalic acid, components that do not have unsaturated bonds in the molecule such as their acid anhydrides and lower alkyl esters, fumaric acid, maleic acid, It includes dicarboxylic acids such as itaconic acid, citraconic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, and endomethylenetetrahydrophthalic acid, as well as components with unsaturated bonds in the molecule such as their acid anhydrides and lower alkyl esters. , of which the latter component has an unsaturated bond in the molecule at 50 mol% or more, preferably 7
It is used in a proportion of 0 mol% or more.

In addition, the B-type polyol component includes ethylene glycol,
Components that do not have unsaturated bonds in their molecules, such as propylene glycol, butanediol, hexanediol, octanediol, decanediol, octadecanediol, or various branched diols, and 2-butene-■・4-diol, 2-5 A component having an unsaturated bond in the molecule such as dimethyl-3-hexene-2,5-diol is included, and among these, the component having an unsaturated bond in the molecule is 50 mol% or more, preferably 70 mol% or more. It is used in a proportion of mol% or more.

The polyester having a repeating unit represented by the general formula (1) is produced by an esterification reaction between one or more of the above type A basic acid components and one or more of the above B type polyol components. However, that @B
A type polybasic acid component and a type A polyol component may be appropriately mixed and used for reaction. In this case, the general formula (I
A polyester having a repeating unit represented by I),
Furthermore, the following general formula (III), (■) ;(A-
C-0-A...(III)1-(B-C-0-B)-...(IV)1 (In both formulas, A and B are the same as above) Although a polyester having repeating units is included, it is preferable that these repeating units (III) and (IV) usually account for 50% or less of all repeating units.

Similarly, a polyester having a repeating unit represented by the general formula (II) is subjected to an esterification reaction with one or more types of B-type polybasic acid components and one or more types of A-type polyol components. In obtaining the polyester, a type A basic acid component and a type B polyol component may be appropriately mixed and used to produce a polyester having repeating units similar to those described above.

In addition, as mentioned above, when producing a polyester having a repeating unit represented by general formula (I) or (]I), when using a B-type polyol component and a B-type child basic acid component together, both of these components are used. It is desirable to set the amount used so that the proportion of the component having an unsaturated bond in the molecule in the total amount of the components is 50 mol % or more.

In addition, for both the above esterification reactions, the above A and B
In addition to the type basic acid component and the A and B type polyol components, other polybasic acid components or polyol components (hereinafter referred to as
As the C-type polybasic acid component or C-type polyol component, for example, aromatic or aralkyl dicarboxylic acids or diols may be used in combination. In this case, the cohesive force of the adhesive may be further improved due to intermolecular interactions.

The amount of the C-type polybasic acid component or C-type polyol component to be used is preferably 20% by weight or less, respectively, in the total polybasic acid component or the total polyol component. This is not preferable because it may adversely affect the properties of being liquid at 25° C. or reduce adhesiveness.

The esterification reaction to obtain an aliphatic polyester that is liquid at room temperature and has a repeating unit represented by the above general formula (1) or (I[) can be carried out using an appropriate catalyst according to a conventional method. In this case, equimolar reaction between the polybasic acid component and the polyol component is desirable, but an excess of either may be used to promote the esterification reaction.

Further, in some cases, a radical polymerization inhibitor may be included in the reaction system in order to prevent gelation due to radical polymerization caused by the component having an unsaturated bond in the molecule.

The degree of reaction is controlled by the acid value or predetermined viscosity of the reaction system. The acid value of polyester that is liquid at room temperature and is desirable as an adhesive is generally 0.2 meq/g or less, and the number average molecular weight of the resulting polyester is in the range of s, o o o to 200.000. It is desirable to do so. If the acid value exceeds the above range and the molecular weight becomes too low, it becomes difficult to balance the cohesiveness and adhesiveness of the adhesive after crosslinking.

The aliphatic polyester of the present invention thus obtained exhibits a liquid state, particularly a viscous fluid state, at room temperature, and has 2 carbon atoms and is composed of the B-type basic acid component and the B-type polyol component described above. As the ~20 aliphatic or alicyclic components, 50 mol% or more of which has an unsaturated bond in the molecule is used, so that it is easily sensitive to actinic radiation.

On the other hand, if the component having the above-mentioned unsaturated bond is less than 50 mol%, the unsaturated bond contained in the component having the hydrogenated 1,2-polybutadiene structure consisting of the A-type polybasic acid component and the A-type polyol component. Although there are some variations depending on the type of adhesive used, the sensitivity is generally insufficient, resulting in a lack of cohesive force of the adhesive.

In the present invention, the above-mentioned aliphatic polyester containing unsaturated bonds is applied to a substrate as it is or diluted appropriately with an organic solvent, and if an organic solvent is used, after drying, active radiation is applied. By irradiating and crosslinking, it becomes an adhesive with improved cohesive force.

At this time, in order to further improve the compatibility of the adhesive, rosin resin, terpene resin, aliphatic petroleum resin, aromatic petroleum resin, alicyclic petroleum resin, coumaron resin, styrene resin, alkylphenol resin A tackifier resin such as resin or xylene resin may be used in combination. In addition, as a chain extender, a substance capable of reacting with the active hydrogen of the polyester, such as a compound such as polyisocyanate or various radically polymerizable compounds, may be added. The amount to be used can be appropriately selected depending on the type of the polyester and its intended use as an adhesive.

As the actinic radiation in the present invention, electron beams, ultraviolet rays, etc. are used as appropriate. In the case of ultraviolet irradiation, it is desirable to add a photopolymerization initiator to the adhesive composition.

Examples of the photopolymerization initiator include methyl benzoin ether, ethyl benzoin ether, isopropyl benzoin ether, isobutyl benzoin ether, ■-phenyl-1,2-propanedione-2(0-ethoxycarbonyl)oxime, 2゜2-dimethoxy-2 -phenylacetophenone, hydroxycyclohexylphenyl ketone, jetoxyacetophenone, 2-hydroxy-2-
Methyl-1-phenylpropan-l-one, benzophenone, benzylmethyl-〇-benzoin benzoate,
Examples include 2-chlorothioxanthone, isopropylthioxanthone, 2-methylthioxanthone, and those in combination with small amounts of sensitizing aids such as amines.

The amount of these photopolymerization initiators used is usually 0.3 to 20 parts by weight per 100 parts by weight of the aliphatic polyester resin.
It may be within the range of parts by weight.

In addition to the above-mentioned components, the adhesive composition of the present invention includes:
Furthermore, various conventionally known additives such as inorganic or organic fillers, powders such as metal powders, pigments, and dyes, particles, and foils can be optionally included.

〔Effect of the invention〕

As described above, in the present invention, by using a specific aliphatic polyester as the main component, a novel material that exhibits excellent adhesiveness and cohesiveness when irradiated with actinic radiation such as electron beams and ultraviolet rays has been developed. A polyester pressure-sensitive adhesive composition can be provided.

〔Example〕

Next, the present invention will be explained in more detail with reference to examples, but the scope of the present invention is not limited in any way by the following examples.

Example 1 A diol having a hydrogenated 1,2-polybutadiene structure [Nl5SOPB G manufactured by Nippon Soda ■] was placed in a four-piece separable flask equipped with a stirrer, a thermometer, and a water separation tube.
I-3000, hydroxyl value 20, 499 milliequivalents/g) 4
00.8g (hydroxyl group = 0゜2 equivalents), maleic anhydride 9.8g (acid group 20.2 equivalents), dibutyltin oxide (hereinafter referred to as DBTO) as a catalyst 50■ (0
. After a while, outflow and separation of water was observed, and the reaction began to proceed.

After continuing the reaction for about 3 hours, the acid value was 0.143 meq/g.
Polyester that is liquid at room temperature (hereinafter referred to as polyester 1A)
) was obtained. Further, the reaction was continued in the same manner for about 6 hours to obtain a polyester (hereinafter referred to as polyester IB) which was liquid at room temperature and had an acid value of 0.053 fi equivalent/g.

After each of these polyesters IA and IB was diluted with toluene to a solid content concentration of 45% by weight, each was divided into two parts, one of which remained as it was to form two types of electron beam-sensitive adhesive compositions, and the other with photopolymerization initiated. As an agent, 4 parts by weight of 2,2-dimethoxy-2-phenylacetophenone (Irgacure 651: manufactured by Ciba Geigy) was added to 100 parts by weight of polyester to form two types of UV-sensitive adhesive compositions. did.

Example 2 328 ml of a diol having a hydrogenated 1,2-polybutadiene structure (NlSOPB G11000 manufactured by Nippon Soda, hydroxyl value: 1.219 meq/g) was placed in the same four rosetteable flasks as in Example 1. .1 g (20.4 equivalents of hydroxyl groups), 11.8 g of maleic anhydride (acid groups:
0.24 equivalent), 16.2 g of sebacic acid (acid group:
0.16 equivalents) and 100 μ(0
, 1 equivalent %), and in the presence of a small amount of toluene as a solvent for discharging reaction water, the temperature was raised to 180° C. while stirring was started, and maintained at this temperature. After a while, outflow and separation of water was observed, and the reaction began to proceed.

After continuing the reaction for about 4 hours, the acid value reached 0.148-3 equivalent/
g of polyester that is liquid at room temperature (hereinafter referred to as polyester 2)
A) was obtained. Further, the reaction was continued in the same manner for about 3 hours to obtain a polyester (hereinafter referred to as polyester 2B) which was liquid at room temperature and had an acid value of 0.051 meq/g.

After each of these polyesters 2A and 2B was diluted with toluene to a solid content concentration of 45% by weight, each was divided into two parts, one of which was used as it was to form two types of electron beam-sensitive adhesive compositions, and the other part was treated with Example 1. 4 parts by weight of the same photopolymerization initiator as in the case of 1 was added to 100 parts by weight of polyester to prepare two types of UV-sensitive pressure-sensitive adhesive compositions.

Example 3 Hydrogenated dicarboxylic acid having a 1,2-polybutadiene structure [
Nl5SOPBCl-1000 manufactured by Nippon Soda ■, acid value:
0.902 milliequivalent/g1443.5g (acid group=0.4
equivalent), 17.6 g of 2-phythene-1,4-diol (
hydroxyl group = 0.4 equivalent), DBTO (previous catalyst) 100
(0.1 equivalent %) and heated to 180°C while starting stirring in the presence of a small amount of toluene as a solvent for discharging reaction water.
and held at this temperature. After a while, outflow and separation of water was observed, and the reaction began to proceed.

After continuing the reaction for about 5 hours, the acid value was 0.146 meq/g.
Polyester that is liquid at room temperature (hereinafter referred to as polyester 3A)
) was obtained. Further, the reaction was continued in the same manner for about 5 hours to obtain a polyester (hereinafter referred to as polyester 3B) which was liquid at room temperature and had an acid value of 0.048 meq/g.

After each of these polyesters 3A and 3B was diluted with toluene to a solid content concentration of 45% by weight, each was divided into two parts, one of which was used as it was to form two types of electron beam-sensitive adhesive compositions, and the other part was prepared with Example 1. Adding 4 parts by weight of the same photopolymerization initiator to 100 parts by weight of polyester,
Two types of ultraviolet-sensitive adhesive m-acids were used.

Each of the adhesive compositions obtained in Examples 1 to 3 above was applied onto a 38 μm thick polyester film using an applicator, dried at 120°C for 5 minutes, and a 50 μm thick adhesive was applied. A coating layer was formed. However, in the case of using an electron beam sensitive type adhesive composition, 3 M r
Crosslinking was carried out by electron beam irradiation. In addition, in the case of using an ultraviolet-sensitive adhesive composition, 200
Crosslinking was carried out by irradiation with ultraviolet light at mJ/cal.

Using these crosslinked films with adhesive layers, we measured the adhesion to a stainless steel plate (SUS 304) (18
0 degree peeling, tensile speed 300 m/min, 23°C) and creep test (vs Bakelite board, load 250 g/c + J,
40°C). The results were as shown in Table 1 below.

From the results in Table 1 above, it is clear that according to the present invention, a novel polyester-based adhesive composition that is sensitive to actinic radiation and exhibits excellent adhesiveness and cohesiveness can be obtained. Recognize.

Claims (3)

[Claims] (1) A component having a hydrogenated 1,2-polybutadiene structure and an aliphatic or alicyclic component having 2 to 20 carbon atoms are used as repeating units, and 5 of the above aliphatic or alicyclic components
An adhesive composition sensitive to actinic radiation, comprising an aliphatic polyester that is liquid at room temperature and is composed of a component having an unsaturated bond in an amount of 0 mol% or more. (2) The pressure-sensitive adhesive composition according to claim 1, which contains a photopolymerization initiator in an amount of 0.3 to 20 parts by weight based on 100 parts by weight of the aliphatic polyester that is liquid at room temperature. (3) Aliphatic polyester that is liquid at room temperature has the following general formula (I) or (II); ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) ▲There are mathematical formulas, chemical formulas, tables, etc. ▼...(II) (In both formulas, A is a divalent group having a hydrogenated 1,2-polybutadiene structure, and B is a divalent group consisting of an aliphatic or alicyclic hydrocarbon having 2 to 20 carbon atoms. A claim consisting of a repeating unit represented by:
The adhesive composition according to 1) or (2).