JPH08209097A - Reactive hot-melt adhesive composition - Google Patents

Abstract

PURPOSE: To obtain a reactive hot-melt adhesive composition composed of an epoxy-modified block copolymer and a polyamide resin and having excellent initial adhesive force, heat-resistant adhesive force, etc. CONSTITUTION: This reactive hot-melt adhesive composition is composed of (I) an epoxy-modified block copolymer produced by epoxidizing the double bond originated from a conjugated diene compound of a block copolymer composed of (A) a polymer block composed mainly of a vinyl aromatic compound and (B) a polymer block composed mainly of a conjugated diene compound or its partially hydrogenated compound existing in the same molecule and (II) a polyamide resin. The epoxy-modified block copolymer preferably has an epoxy equivalent of 250-2,000.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a reactive hot melt adhesive composition comprising a block copolymer having an epoxy-modified specific structure and a polyamide resin, and having excellent initial adhesive strength and heat resistant adhesive strength, and The present invention relates to an adhesive composition having excellent storage stability and workability.

[0002]

2. Description of the Related Art Hot-melt adhesives can be applied to a wider range of adherends than other adhesives, no solvent is used, and there is no danger of toxicity or fire. It is widely used in the fields of bookbinding, packaging, shoes, can manufacturing, sewing, and woodworking because it has good advantages. However, since this type of adhesive uses a thermoplastic resin as a base polymer and has a relatively low melting point from the viewpoint of coatability, it is inferior in heat resistance and has a limited field of application. Recently, many patents have been published regarding the reactive hot melt adhesives having improved heat resistance. For example, in Japanese Unexamined Patent Publication No. 1-284577, a urethane prepolymer containing a mixed polyol of a terminal hydroxyl group-containing hydrocarbon-based polyol and polyoxybutylene glycol, polyisocyanate, a thermoplastic block copolymer, and an acid value A reactive hot-melt adhesive composition is described, which comprises a tackifier made of a rosin derivative having a hydroxyl value of 5 or less and a hydroxyl value of 35 or less. However, since the curing reaction of this adhesive proceeds with the water content in the air, the curing reaction does not proceed at the portion not in contact with the air, and the heat-resistant adhesive strength is not sufficient. In addition, a special applicator is required because the curing reaction will proceed if it comes into contact with air before coating. In addition, there are problems such as poor storage stability.

[0003]

Thus, the present invention solves the above problems by using a reactive hot melt adhesive, that is, it has excellent heat resistant adhesive strength, storage stability, workability, and initial adhesive strength. It is an object to provide a reactive hot melt adhesive.

[0004]

That is, the present invention is as follows.
(A) A block composed of a polymer block (A) mainly containing a vinyl aromatic compound in the same molecule and a polymer block mainly containing a conjugated diene compound or a partially hydrogenated polymer block (B) thereof A reactive hot melt adhesive composition comprising an epoxy-modified block copolymer in which a double bond derived from a conjugated diene compound of the copolymer is epoxidized, and (b) a polyamide resin, preferably an epoxy-modified block copolymer. Has an epoxy equivalent of 250-2
000, and preferably 1 mol of epoxy groups contained in the epoxy-modified block copolymer,
The free amino group contained in the polyamide resin is 0.1 to 1
The present invention relates to a reactive hot melt adhesive compounded to be 0 mol. Hereinafter, the present invention will be described in detail.

The vinyl aromatic compound constituting the polymer block (A) mainly containing the vinyl aromatic compound of the block copolymer which is a raw material of the epoxy modified block copolymer used in the present invention is, for example, styrene, α-methylstyrene, vinyltoluene, p-tertiary butylstyrene, divinylbenzene, p-methylstyrene, 1,1-
One kind or two or more kinds can be selected from diphenylstyrene and the like, and styrene is preferable. Further, as the conjugated diene compound constituting the polymer block mainly composed of the conjugated diene compound of the block copolymer or the partially hydrogenated polymer block (B) thereof, for example, butadiene,
Isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl-1,
One kind or two or more kinds are selected from 3-octadiene, phenyl-1,3-butadiene and the like, and among them, butadiene, isoprene and a combination thereof are preferable.

The block copolymer referred to herein is a block copolymer composed of a polymer block A containing a vinyl aromatic compound as a main component and a polymer block B containing a conjugated diene compound as a main component. The copolymerization molar ratio of the group compound and the conjugated diene compound is 5/95 to 70/30, and particularly preferably 10/90 to 60/40.
The weight average molecular weight of the block copolymer, which is a raw material of the epoxy-modified block copolymer used in the present invention, is 10,
000 to 400,000, preferably 50,000 to 2
The molecular weight distribution is [the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw / M).
n)] is preferably 10 or less. The molecular structure of the block copolymer may be linear, branched, radial, or any combination thereof.
For example, A-B-A, B-A-B-A, (A-B-) ₄
It is a vinyl aromatic compound-conjugated diene compound block copolymer having a structure such as Si or ABABABA.
Further, the unsaturated double bond derived from the conjugated diene compound of the block copolymer may be partially hydrogenated, and the hydrogenation rate of the unsaturated double bond derived from the conjugated diene compound is 0 to 8
It is preferably 0%, particularly preferably 10 to 70%.

The block copolymer, which is a raw material for the epoxy-modified block copolymer used in the present invention, may be produced by any method as long as it has the above-mentioned structure. For example, the vinyl aromatic compound-conjugated diene compound block copolymer can be produced in an inert solvent using a lithium catalyst or the like by the method described in JP-B-40-23798. Further, hydrogenation is carried out in the presence of a hydrogenation catalyst in an inert solvent by the method described in JP-B-42-8704, JP-B-43-6636 or JP-A-59-133203, A partially hydrogenated block copolymer, which is a raw material for the epoxy-modified block copolymer used in the present invention, can be produced.

The epoxy-modified block copolymer used in the present invention can be obtained by epoxidizing the above block copolymer. That is, the epoxy-modified block copolymer can be obtained by reacting the above block copolymer with an epoxidizing agent such as hydroperoxides and peracids in an inert solvent.

The hydroperoxides include hydrogen peroxide, tertiary butyl hydroperoxide,
Cumene peroxide and the like are exemplified. Examples of peracids include formic acid, peracetic acid, perbenzoic acid and trifluoroperacetic acid. Of these, peracetic acid is a preferred epoxidizing agent because it is industrially produced in large quantities, can be obtained at low cost, and has high stability.

A catalyst can be used if necessary in the epoxidation. For example, in the case of peracids, an alkali such as sodium carbonate or an acid such as sulfuric acid can be used as a catalyst. On the other hand, in the case of hydroperoxides, a mixture of tungstic acid and caustic soda is used as hydrogen peroxide, an organic acid is used as hydrogen peroxide, or molybdenum hexacarbonyl is used as tertiary butyl hydroperoxide to obtain a catalytic effect. be able to.

There is no strict regulation on the amount of epoxidizing agent used, and the optimum amount in each case depends on the particular epoxidizing agent used, the desired degree of epoxidation, the individual block copolymer used, etc. It depends on such variable factors.

The inert solvent can be used for the purpose of lowering the viscosity of the raw material and stabilizing it by diluting the epoxidizing agent. In the case of peracetic acid, aliphatic hydrocarbons and aromatic hydrocarbons are used. , Halogenated hydrocarbons, ethers,
Esters and the like can be used. Particularly preferred solvents are hexane, cyclohexane, toluene, benzene, ethyl acetate, carbon tetrachloride, chloroform. There is no strict limitation on the epoxidation reaction conditions. The reaction temperature range that can be used is determined by the reactivity of the epoxidizing agent used. For example, in the case of peracetic acid, 0 to 70 ° C is preferable,
If the temperature is lower than 0 ° C, the reaction is slow, and if it exceeds 70 ° C, decomposition of peracetic acid occurs. In the tertiary butyl hydroperoxide / molybdenum hexacarbonyl system which is an example of hydroperoxide, the temperature is 20 to 150 ° C. for the same reason.
Is preferred. No special operation is required in the reaction, for example,
The raw material mixture may be stirred for 2 to 10 hours.

Isolation of the resulting epoxy modified copolymer is
It can be carried out by an appropriate method, for example, a method of precipitating with a poor solvent, a method of putting the polymer in hot water with stirring and removing the solvent by distillation, a direct desolvation method and the like.

The epoxy-modified block copolymer (a) used in the present invention usually has a vinyl aromatic compound structural unit content of 5 to 70% by weight, preferably 10 to 60% by weight. The weight average molecular weight of the epoxy-modified block copolymer (a) used in the present invention is preferably 10,000 to 500,000, more preferably 5
If it is less than this range, the cohesive force will decrease, and if it is more than this range, the melt viscosity will increase and the workability will deteriorate. Further, the epoxy equivalent of the epoxy-modified block copolymer used in the present invention is preferably in the range of 250 to 2,000, more preferably 250 to 1,000. If the epoxy equivalent is less than 250, the initial adhesive strength will decrease, and if it exceeds 2,000, the heat resistant adhesive strength will decrease.

Another essential component used in the present invention is a polyamide resin as an epoxy resin curing agent. Curing compositions of epoxy resins and polyamide resins are already known, for example US Pat. No. 2,705,22.
3, U.S. Pat. No. 4,082,708, U.S. Pat. No. 2,867,592, U.S. Pat. No. 3,488,665.
No. 6-32877. However, no report has been made on a reactive hot melt adhesive composed of an epoxy-modified block copolymer and a polyamide resin.

The preferred polyamide resin of the present invention is obtained from polymerized fatty acid; linear dicarboxylic acid; and linear, branched or cyclic polyamine or a mixture thereof, and the total value of amine value and acid value is from 1 to 1. It is in the range of 50 and has an excess of amino groups (free amino groups) with respect to acid groups (carboxyl groups) (here, the amine value is represented by mg equivalent-KOH / g-sample value). . The number of amino groups in the polyamide resin is preferably between about 51% and about 99% of the total value of acid groups and amino groups. When the functionality (the total value of amine value and acid value) becomes lower, the amino groups are excessively dispersed and the resin does not cure sufficiently.
If the functionality is too high, there is a risk of premature gelation or excessive viscosity. The softening point of the polyamide resin is usually 50 ° C or higher, preferably 70 to 200 ° C.

The polymerized fatty acid refers to an acid commercially known as "dimer acid" or a non-linear dicarboxylic acid, particularly a non-linear dicarboxylic acid having 21 to 44 carbon atoms. The amount of dimer acid in the polyamide resin is 50-
It is 90 equivalent%, more preferably 65 equivalent% or more.

The linear dicarboxylic acid has 6 to 22 carbon atoms and includes oxalic acid, malonic acid, succinic acid, adipic acid,
Examples include azelaic acid and sebacic acid. Usually, the amount of linear dicarboxylic acid can be added in an amount of up to about 70 equivalent%, preferably 10 to 15 equivalent% of the total carboxylic acid components.

Monocarboxylic acids can be added to change the ratio of amino groups to acid groups and / or to control the molecular weight of the polyamide resin. Preferred monocarboxylic acids are linear and have 2 to 22 carbon atoms,
Examples include stearic acid and oleic acid. The amount of monocarboxylic acid can be added up to about 10 equivalent% of the total carboxylic acid component.

The linear, branched or cyclic polyamine or a mixture thereof has 2 to 60 carbon atoms and is mainly a diamine. Preferred fatty acid polyamines include ethylenediamine, diaminopropane, diaminobutane, diaminopentane, hexamethylenediamine, methylpentamethylenediamine, methylnonanediamine,
Piperazine, dipiperazine, aminoethylpiperazine,
There are bis (aminoethyl) piperazine, bis (aminoethyl) cyclohexane and dimer diamines (diamines made from dimer acid). Particularly preferred are ethylenediamine, piperazine, methylpentamethylenediamine, dimerdiamine and polyetherdiamine. The amount of polyamine or mixture thereof is from about 100 equivalent% to 120 equivalent%, more preferably from 100 equivalent% to 115 equivalent%, based on the total acid groups added to the polymerization system. Add.

Polyether diamines provide products with good flow properties. A preferred polyether diamine is a diamine made from an ethylene oxide polymer having a molecular weight of 100-800, a molecular weight of 100-8.0.
And a diamine made from an ethylene oxide-propylene oxide polymer having a molecular weight of 100 to 8,000. The amount of polyether diamine is 2 to 60 equivalent%, more preferably 5 to 40 equivalent%.

It is also possible to add up to 10 equivalent% of monoamine in order to control the molecular weight and functionality. In addition, polyvalent amines such as diethylenetriamine, triethylenetetramine, and tetraethylenepentamine can be used as 3% of total amines.
It can be added up to 0 equivalent%.

For the purpose of reducing the viscosity of the polyamide resin without adversely affecting the physical strength characteristics of the adhesive composition, a diluent having polar groups such as amines, amides, esters, ethers and sulfides having a molecular weight of 200 to 900. 0.01-0.3 to 100 parts by weight of polyamide resin
Parts by weight, more preferably 0.03 to 0.2 parts by weight can be added. When the molecular weight is less than 200, it becomes difficult to maintain the volatility on the basis that the hot melt adhesive can be used without boiling during use. Molecular weight is 9
If it exceeds 00, the effect of lowering the melt viscosity of the polyamide resin becomes small. Further, the boiling point of the diluent is preferably 290 ° C. or higher from the above points.

The preferred amine diluent is tallow amine,
These are ditallow amine (Note 1) and di (hydrogenated tallow) amine. Diamines such as tallow aminopropyl amine and dimer diamines are also useful as diluents. Both primary amines and secondary amines may be used as diluents. Monoamines are generally preferred over diamines. Particularly preferred are secondary monoamines such as ditallow amine. In addition, amides such as stearyl stearamide and ethylene bis stearamide can also be used.

In the reactive hot melt adhesive composition of the present invention, the free amino group contained in the polyamide resin is preferably 0. 0, based on 1 mol of the epoxy group contained in the epoxy modified block copolymer. It is in the range of 1 to 10 mol, particularly preferably 0.1 to 5 mol. By using the polyamide resin in the ratio of the preferred range,
An adhesive composition having excellent initial adhesive strength and storage stability can be obtained.

The reactive hot melt adhesive of the present invention comprises
A curing accelerator may be used in combination with the epoxy-modified block copolymer and the polyamide resin. As a curing accelerator,
Cresol, phenolic acid, phenols such as isopropylphenol, salicylic acid, p-toluenesulfonic acid, 2-
An organic acid such as ethylhexanoic acid.

In the present invention, generally used additives such as tackifiers and softeners can be added as long as the properties of the reactive hot melt adhesive are not impaired.

The tackifier used in the present invention includes:
Rosin resin, modified rosin resin, polyterpene resin, synthetic polyterpene resin, alicyclic hydrocarbon resin,
A coumarone resin, an aromatic hydrocarbon resin, an aliphatic hydrocarbon resin, a styrene petroleum resin, etc. can be used. this house,
Particularly preferred are rosin-based resins, polyterpene-based resins and alicyclic hydrocarbon resins. These tackifiers can be used alone or in admixture of two or more.

As the softening agent used in the present invention, various liquid rubbers such as naphthene type process oil and paraffin type process oil, for example, liquid polyisoprene rubber, liquid polyacrylate, liquid polybutene, liquid polyisoprene isobutylene rubber, liquid Acrylic rubber and liquid polybutadiene rubber can be used. These softening agents may be used alone or in admixture of two or more.

In addition to the above, the reactive hot melt adhesive composition of the present invention may further contain, if necessary, antioxidants, stabilizers such as ultraviolet absorbers, calcium carbonate, silica, talc, clay, titanium oxide and carbonic acid. Inorganic fillers such as magnesium and carbon black, colorants, pigments and the like may be added. Further, in the reactive hot melt adhesive composition of the present invention, other rubber component or resin component may be added as long as the properties as the hot melt adhesive are not impaired. Examples of such optional components include natural rubber, polyisoprene rubber, polybutadiene rubber, SBR, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, high styrene rubber, chloroprene rubber, EPT, EPR, Elastomers such as acrylic rubber and polyisoprene isobutylene rubber, and thermoplastic resins such as 1,2-polybutadiene rubber, polybutene, polyethylene, ethylene-vinyl acetate copolymer, partially saponified ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate. In addition to ethylene-based copolymers such as copolymers, atactic polypropylene and ionomers, polystyrene, styrene-acrylonitrile copolymer, AB
You may add 1 type (s) or 2 or more types of styrene resin, such as S and MBS.

In the adhesive composition of the present invention, these components are heated in a general tank mixer, a closed kneader, an extruder, a mixing roll, a Banbury mixer, etc. under heating and, if necessary, an inert gas atmosphere. Obtained by mixing below.

[0031]

The present invention will be described in more detail with reference to the following examples. The examples are representative of the invention,
It does not limit the scope of the invention.

(Production Example 1) A polystyrene-polybutadiene-polystyrene block copolymer A'was placed in a jacketed reactor equipped with a stirrer, a reflux condenser and a thermometer.
[Nippon Synthetic Rubber Co., Ltd., trade name: TR2000] 30
0 g and 1,500 g of ethyl acetate were charged and dissolved. Then, 169 g of a 30 wt% ethyl acetate solution of peracetic acid was continuously added dropwise to carry out an epoxidation reaction at 40 ° C. for 3 hours while stirring. The reaction solution is returned to room temperature and taken out from the reactor, a large amount of methanol is added to precipitate a polymer, and the polymer is filtered and washed with water,
It was dried to obtain an epoxy-modified block copolymer. The obtained epoxy-modified block copolymer is referred to as polymer A. The epoxy equivalent of polymer A was 470.

(Production Example 2) A block copolymer B'of polystyrene-polybutadiene-polystyrene was added to a jacketed reactor equipped with a stirrer, a reflux condenser and a thermometer.
[Nippon Synthetic Rubber Co., Ltd., trade name: TR2400] 30
0 g and 1,500 g of ethyl acetate were charged and dissolved. Then, 113 g of a 30 wt% ethyl acetate solution of peracetic acid was continuously added dropwise, and an epoxidation reaction was carried out at 40 ° C. for 3 hours while stirring. The reaction solution is returned to room temperature and taken out from the reactor, a large amount of methanol is added to precipitate a polymer, and the polymer is filtered and washed with water,
It was dried to obtain an epoxy-modified block copolymer. The obtained epoxy-modified block copolymer is referred to as polymer B. The epoxy equivalent of polymer B was 698.

(Production Example 3) A polystyrene-polybutadiene-polystyrene block copolymer C'was placed in a jacketed reactor equipped with a stirrer, a reflux condenser and a thermometer.
[Shell Chemical Co., Ltd., trade name: Califlex D11
22] 300 g and cyclohexane 1,500 g were charged and dissolved. Then, 177 g of a 30 wt% ethyl acetate solution of peracetic acid was continuously added dropwise, and an epoxidation reaction was carried out at 40 ° C. for 3 hours with stirring. The reaction solution is returned to room temperature and taken out from the reactor, a large amount of methanol is added to precipitate a polymer,
After filtering, it was washed with water and dried to obtain an epoxy-modified block copolymer. The obtained epoxy-modified block copolymer is referred to as polymer C. The epoxy equivalent of polymer C was 445.

(Production Example 4) A polystyrene-polyisoprene-polystyrene block copolymer D'was placed in a jacketed reactor equipped with a stirrer, a reflux condenser and a thermometer.
[Shell Chemical Co., Ltd., trade name: Califlex TR1
111] 300 g and cyclohexane 1,500 g were charged and dissolved. Then, 222 g of a 30 wt% ethyl acetate solution of peracetic acid was continuously added dropwise, and an epoxidation reaction was carried out at 40 ° C. for 3 hours while stirring. The reaction solution was returned to room temperature, taken out from the reactor, a large amount of methanol was added to precipitate a polymer, and the polymer was filtered, washed with water and dried to obtain an epoxy-modified block copolymer. The obtained epoxy-modified block copolymer is referred to as polymer D. The epoxy equivalent of polymer D is 35
It was 6.

(Examples 1 to 4 and Comparative Examples 1 to 4) Polymers A, B, C and D obtained in Production Examples 1 to 4 were used in Examples, and used in Comparative Examples in Production Examples. The block copolymers A ′, B ′, C ′ and D ′ were added to a compounding tank heated to 120 ° C. according to the compounding ratios shown in Table 1, and mixed and stirred for 1 hour to obtain each adhesive. Got

The adhesives thus obtained were subjected to various adhesion tests according to the following methods. The test method is shown below. Initial Adhesion Test: An adhesive was heated and melted at 200 ° C. for 5 minutes and applied to an adherend, and an adhesion test was performed immediately after pressing (2 Kg, 1 minute). Use a stainless steel plate for the adherend,
Adhesive area 25 × 25 mm, adhesive thickness 1 mm, pulling speed 100 mm / min (20 ° C.), adhesive force (kg
f / inch ² ) was measured. Heat-resistant adhesive strength test: According to the above method, the adhesive strength at 80 ° C. × 96 hours and 100 ° C. × 24 hours was measured. Table 2 shows the measurement results.

[0039]

[Table 1]

[0040]

[Table 2]

[0040]

The reactive hot melt adhesive of the present invention is
Honeycomb, plywood, because of excellent initial adhesive strength and heat resistant adhesive strength
It is effective as an adhesive in the fields where plastic foam, composite panels composed of inorganic and metal plates, etc., high adhesive strength for automobile doors, instrument panels, head lamps, tail lamps, windows, etc., and heat resistance are required. is there.

Claims (3)

[Claims] (A) A polymer block (A) mainly containing a vinyl aromatic compound in the same molecule, and a polymer block (B) mainly containing a conjugated diene compound or a partially hydrogenated polymer block (B) thereof. And (b) a reactive hot-melt adhesive composition comprising an epoxy-modified block copolymer obtained by epoxidizing a double bond derived from a conjugated diene compound of a block copolymer comprising: and (b) a polyamide resin. 2. The reactive hot melt adhesive composition according to claim 1, wherein the epoxy equivalent of the epoxy-modified block copolymer is in the range of 250 to 2,000. 3. A free amino group contained in the polyamide resin is 0.1 to 10 moles based on 1 mole of the epoxy group contained in the epoxy modified block copolymer and the polyamide resin. The reactive hot melt adhesive composition according to claim 1 or 2, which is blended as follows.