JPH0270786A - Self-adhesive resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition having good tackiness to polyolefin material, cohesiveness, and durability by incorporating an isocyanate compound into a silylated and hydroxylated ethylene terpolymer made by copolymerization in the presence of a chlorinated polyolefin resin. CONSTITUTION:The title composition is obtained by mixing a polymer (A) containing a chlorinated polyolefin (having an Mw of 150,000 to 500,000, preferably 200,000 to 400,000, a polydispersity index of 3 to 7, preferably 3 to 5, and a glass transition temperature of -70 to -30 deg.C, preferably -50 to -40 deg.C) with an isocyanate compound (B) in an amount sufficient to provide an equivalent ratio of component B to the hydroxyl group of component A of (0.7-5):1. The polymer A is prepared by polymerizing a mixture composed of 0.01-5wt.% unsaturated organosilane compound of the formula (wherein X is a group containing copolymerizable double bonds; Y is a hydrolyzable group or halogen; n is 1 to 3, and m is 0 to 2, provided that m + n = 3), 75-99.39wt.% ethylenically unsaturated monomer, and 0.1-5wt.% hydroxylated monoethylenically unsaturated monomer, in the presence of a chlorinated polyolefin resin having a chlorine content of 50wt.% of less.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a resin composition for a solvent-type acrylic pressure-sensitive adhesive, and in particular, to a resin composition for a solvent-type acrylic pressure-sensitive adhesive. The present invention relates to a resin composition for adhesives that has good adhesion, cohesiveness, and heat resistance to objects to be adhered.

[Conventional technology]

Acrylic adhesives are used for tapes, labels, stickers, seals, etc., and the materials to which they are adhered include plastics, metals, glass, paper, ceramics, surface protection films, etc. In particular, the number of plastic products has been increasing more and more in recent years, and the proportion of polyolefin resins among plastic products has been increasing significantly.

Therefore, there is a need for adhesives that have good adhesion to polyolefins, cohesive properties, and heat resistance.

The adhesion and cohesive force of acrylic adhesives are generally adjusted by changing the monomer composition, adding tackifying resins such as phenolic resins, rosin-modified resins, petroleum-modified resins, etc., and adding liquid plasticizers. .

Furthermore, in addition to acrylic resins, resins such as ethylene-vinyl ester copolymer, natural rubber, synthetic rubber, and polyvinyl alkyl ether are used in combination to improve the properties of the adhesive. It is also known to blend low-molecular-weight acrylic resin and high-molecular-weight acrylic resin to increase adhesive strength and cohesive force (see JP-A-61-4772 and JP-B-61-57354). .

In addition, when the acrylic adhesive used for the adhesive is a solvent type, the weight average molecular weight is 100.000 to 200.00.
0, molecular weight dispersity (weight average molecular weight/number average molecular weight) 8
~15, an acrylic resin with a glass transition temperature of -50°C to -30°C is used, and if necessary, it is cured with an isocyanate compound to increase cohesive strength.

[Problem to be solved by the invention]

Conventional acrylic pressure-sensitive adhesive resin compositions are inferior in adhesion to polyolefin substrates, cohesiveness, and heat resistance. Therefore, many attempts have been proposed to improve the performance of adhesives for polyolefin substrates.

For example, there is a method of increasing the molecular weight of a resin composition, but increasing the molecular weight also increases the amount of low molecular weight substances, and as a result, the performance does not improve much. In addition, in the method of adding a tackifier and plasticizer, the resin added has a low molecular weight and a low softening point in consideration of compatibility with the acrylic resin, but since it is liquid, it has a low heat resistance. will decrease. In addition, the functional groups copolymerized into acrylic resin are generally distributed in relatively low molecular weight regions, so depending on the type of solvent, solubility may decrease and resin viscosity may increase, resulting in decreased workability. . Furthermore, since the functional groups are unevenly distributed, even when reacted with an isocyanate compound and cured,
The structure becomes non-uniform, and the cohesive force and heat resistance do not improve.

Moreover, when the crosslinking density is increased, the cohesiveness and heat resistance are improved, but the tackiness is decreased.

Therefore, the present invention eliminates the above-mentioned drawbacks and provides an excellent adhesive resin composition that has well-balanced properties such as adhesion to polyolefin substrates, cohesiveness, and heat resistance.

[Means to solve the problem]

The present invention solves the above problems by combining a specific chlorinated polyolefin-containing polymer composition and an isocyanate compound. That is, the present invention provides general formula (1): % formula % (1) [wherein X represents a group having a copolymerizable double bond, and Y
represents a hydrolyzable group or halogen, R represents an inert monovalent organic group, n represents the number of bonds in Y and represents an integer of 1 to 3, m represents the number of bonds in R and represents Oll or 2. and m+n is 3] 0.0
1 to 5 weight percent, ethylenically unsaturated monomer 75 to 99.3
A formulation containing 9% by weight and 0.1 to 5% by weight of a monoethylenically unsaturated monomer having a hydroxyl group is mixed with 0.5 to 15% by weight of a chlorinated polyolefin resin with a chlorine content of 50% or less. Weight average molecular weight obtained by polymerization in the presence of
0,000 to 500,000, a molecular weight dispersity of 3 to 7, and a glass transition temperature of -70°C to -30°C, a chlorinated polyolefin-containing polymer (A) and an incyanate compound (
The present invention relates to a resin composition for adhesives containing B).

As mentioned above, the blend of polymerizable monomers used in the present invention contains 0.01 to 5% by weight, preferably 0.1 to 2% by weight of the unsaturated organic silane compound represented by the general formula (1). include. By using the unsaturated organic silane compound, the cohesiveness and heat resistance of the polyolefin material can be improved.

If the amount of the unsaturated organosilane compound is less than 0.01% by weight, this improvement effect will be small, and if it exceeds 5% by weight, hydrolyzable groups will be hydrolyzed during polymerization and crosslinking reaction will occur, resulting in It becomes easier to gel.

In the general formula (1), X is a group having a copolymerizable double bond, such as a vinyl group, an allyl group, an alkenyl group such as a butenyl group, a cyclohexenyl group, a cyclopentagenyl group, a cyclohexagenyl group, etc. cycloalkenyl groups such as groups, unsaturated acyloxyalkyl groups such as γ-methacryloxypropyl M, unsaturated acyloxyalkoxy groups such as γ-methacryloxyethylpropyl ether, CHz =
C(CHi)COO(CHz)z○CHz CH(OH
) CHz O (CHZ): + group, etc. Among these, the most preferred are unsaturated acyloxyalkyl groups such as T-methacryloxypropyl group or unsaturated acyloxyalkoxy groups such as γ-methacryloxyethylpropyl ether group.

Among the groups Y, the hydrolyzable group is preferably an alkoxy group having 1 to 6 carbon atoms, an acyloxy group having 1 to 6 carbon atoms, an oximo group having 1 to 14 carbon atoms, and the like, such as a methoxy group. , ethoxy group, alkoxy group such as butoxy group, acyloxy group such as formyloxy group, acetoxy group, propyleneoxy group, etc., ON =
C(CH3):l, -0N=C(CH3)C2H5,
oximo groups such as ON=C(CbHs)z, etc.
A group that generates a hydroxyl group by hydrolysis, N HCH3, -
These include NHC, H, and an alkylamino group or arylamino group such as -NH (C, H,). The radical Y may also be a halogen atom, for example chlorine, fluorine, bromine or iodine. When n is 2 or 3, the groups Y may be the same or different.

The group R is an inert monovalent organic group, preferably a hydrocarbon group having 1 to 18 carbon atoms, such as a methyl group,
These include alkyl groups such as ethyl, propyl, butyl, tetradecyl and octadecyl groups, aryl groups such as phenyl, benzyl and tolyl groups, aralkyl groups and alkaryl groups. When m is 2 or 3, the groups R may be the same or different.

Examples of the unsaturated organic silane compound represented by the general formula (1) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(2-methoxyethoxy)
Silane, vinylmethyldimethoxysilane, vinylmethyldimethoxysilane, T-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltri(2
-methoxyethoxy)silane, T-acryloxypropyltriethoxysilane, vinyltrichlorosilane, etc.

The group Y in the unsaturated organosilane compound represented by general formula (I) reacts with moisture in the raw materials or polymerization solvent used,
Hydrolysis or substitution reactions result in hydroxyl groups or groups having hydroxyl groups, etc., and functional groups such as hydroxyl groups may undergo crosslinking reactions (e.g. dehydration reactions) during polymerization reactions and/or when creating adhesive compositions. can.

The blend of polymerizable monomers used in the present invention contains 75 to 99.39% by weight of ethylenically unsaturated monomers, as described above. Desired characteristics cannot be obtained outside this range.

Examples of ethylenically unsaturated monomers include methyl acrylate,
Acrylic acid alkyl esters such as ethyl acrylate, butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, cyclohexyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, methacrylic acid methacrylic acid alkyl esters such as 2-ethylhexyl, lauryl methacrylate, and cyclohexyl methacrylate; unsaturated acids such as methacrylic acid and acrylic acid;
Styrenic monomers such as styrene, vinyltoluene, and α-methylstyrene; vinyl derivatives such as vinyl chloride, hnylidene chloride, vinyl acetate, and isopropenyl acetate; unsaturated dibasic acids such as maleic acid and fumaric acid; and their acid anhydrides. monoalkyl esters thereof, such as monomethyl esters and monoethyl esters, or dialkyl esters thereof such as dimethyl esters and diethyl esters, glycidyl methacrylate, glycidyl acrylate, methacrylamide, acrylamide, and the like. In addition, in the above-mentioned compound, alkyl also includes the meaning of cycloalkyl. Further examples of the ethylenically unsaturated monomer include divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate,
Diethylene glycol diacrylate, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, pentaerythritol trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetramethacrylate, pentaerythritol tetraacrylate, etc. There are monomers having two or more ethylenically unsaturated double bonds.

Among the above monomers, monomers having two or more ethylenically unsaturated double bonds are used in an amount of 5% by weight or less based on the total amount of ethylenically unsaturated monomers used. is preferable. If the amount is too large, gelation tends to occur during polymerization.

As a monoethylenically unsaturated monomer having a hydroxyl group,
2-hydroxyethyl methacrylate, 2-hydroxyethyl methacrylate
Hydroxyalkyl methacrylates such as hydroxypropyl, 2-hydroxybutyl methacrylate, 2-hydroxypentyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 2-hydroxypentyl acrylate There are hydroxyalkyl acrylates such as.

The monoethylenically unsaturated monomer having such a hydroxyl group is blended in an amount of 0.1 to 5% by weight. These monomers are 5
If it exceeds 0.1% by weight, the solubility in the solvent will decrease, the uniformity of the resin will be impaired, and the stability will decrease.
If it is less than that, crosslinking will be insufficient and heat resistance and cohesiveness will decrease.

After blending the above components, a polymerization reaction is carried out in the presence of 0.5 to 15% by weight of a chlorinated polyolefin resin having a chlorine content of 50% by weight or less.

The above-mentioned chlorinated polyolefin resins include polyethylene resins, polypropylene resins, ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, etc. having a chlorine content of 50% by weight or less. When the chlorine content exceeds 50% by weight, the adhesion to polyolefin materials decreases. The chlorine content is preferably 15 to 35% by weight.

The chlorinated polyolefin resin having a chlorine content of 50% by weight or less needs to be present in an amount of 0.5 to 15% by weight during the polymerization of the polymerizable monomer. Outside this range, adhesion to many types of materials is poor (high adhesion can only be achieved with specific materials).

The total amount of the unsaturated organosilane compound represented by the general formula (1), the ethylenically unsaturated monomer, the monoethylenically unsaturated monomer having a hydroxyl group, and the chlorinated polyolefin resin with a chlorine content of 50% by weight or less is is used so that it is 100% by weight.

The polymerization reaction is carried out by a known radical polymerization method, but the method is not particularly limited. for example,
The continuous polymerization method in which polymerization is carried out at 60 to 130°C is a known polymerization method, and the polymer (A) can be easily synthesized by appropriately selecting conditions in the continuous synthesis method.

For example, a mixture of an ethylenically unsaturated monomer, a chlorinated polyolefin, an unsaturated organic silane compound represented by the general formula (1,), a monoethylenically unsaturated monomer having a hydroxyl group, a solvent, a polymerization initiator, etc. This is a method in which the polymer is continuously supplied to a reactor, a polymerization reaction is carried out, and a polymer is continuously obtained.

During polymerization, the polymerization rate, molecular weight, and molecular weight dispersity can be arbitrarily adjusted and determined by synthesis temperature, polymerization initiator concentration, ethylenically unsaturated monomer concentration, blend supply rate, and blend residence time. In this case, the organic solvents include aromatic solvents such as toluene and xylene, methyl ethyl ketone,
Ketone solvents such as methyl isobutyl ketone, ester solvents such as ethyl acetate and butyl acetate, and chlorine solvents such as carbon tetrachloride can be used. Further, as the polymerization initiator, organic peroxides such as benzoyl peroxide, dicumyl peroxide, and dibutyl peroxide, or azobis-based compounds such as azobisisobutyronitrile, etc. can be used.

The polymer thus obtained is prepared by removing unreacted monomers (e.g., distilled off under reduced pressure) as necessary, dissolving it in an appropriate organic solvent, and adding other (B ) components, etc., to form a resin composition for adhesives. As the organic solvent used in this case, those exemplified as the organic solvents mentioned above can be used.

The polymer (A) has a weight average molecular weight of 150,000 to 5
00.000 and 200,000
It is preferable that it is 400,000. When the weight average molecular weight of this polymer is less than 150,000, sufficient adhesive performance cannot be obtained, and when it exceeds 500,000, the viscosity becomes high and workability decreases.

The molecular weight dispersity of the polymer (A) needs to be 3-7, preferably 3-5. If the molecular weight dispersity of the polymer (A) exceeds 7, the amount of low molecular weight substances will increase, making it impossible to obtain sufficient performance.

The degree of molecular weight dispersion can be determined by, for example, performing gel permeation chromatography on the polymer (A), calculating the number average molecular weight t (Mn) in terms of polystyrene from the obtained chromatogram, and M w from the weight average molecular weight (Mw). /
It can be known as M n .

Further, the glass transition temperature of the polymer (A) is -70
It is necessary to be between °C and -30°C, preferably between -50 and 40°. If the glass transition temperature is less than 170°C, performances such as heat resistance and workability will deteriorate. -30°C
If it exceeds , the tackiness decreases.

The glass transition temperature can be determined, for example, using a thermal mechanical tester for polymer (A).
It can be determined by the invasion method using TMA).

The isocyanate compound as component (B) used in the resin composition of the present invention includes an adduct of tolylene diisocyanate and trimethylolpropane, an adduct of hexamethylolpropane, and a form of hexamethylene diisocyanate bonded with a biuret bond. There are isocyanate compounds such as a cyclic trimer of hexamethylene diisocyanate and a cyclic trimer of isophorone diisocyanate, and blocked isocyanates in which all or some of the isocyanate groups of these compounds are blocked with a blocking agent.

The above-mentioned isocyanate compound is preferably blended in an amount of 0.7 to 1.5 equivalents per equivalent of hydroxyl group in the polymer (A). If this amount is less than 0.7 equivalent, crosslinking will be insufficient, resulting in decreased heat resistance and cohesiveness,
If the blending amount exceeds 1.5 equivalents, the tackiness tends to decrease.

The resin composition for adhesives according to the present invention is as described above (A
) and (B) components, and appropriate solvents and additives can be added as necessary.

The adhesive resin composition according to the present invention can be applied to a roll coater,
It can be applied by conventional methods such as spray painting, and can be used as an adhesive for sheets, films, and other various molded products made of polyolefin materials.

〔Example〕

Next, the present invention will be explained with reference to Examples, but the present invention is not limited thereto. In the following, "parts" and "%" mean "parts by weight" and "% by weight", respectively, unless otherwise specified.

Examples 1 to 3 400 rttl of toluene was put into a continuous polymerization apparatus having a reactor equipped with a stirrer, heated to 90°C, and the formulation shown in Table 1 was fed at a rate of 0.36 kg/hr. , Continuous polymerization was started, and after 4 hours had passed, the polymer was collected. Table 1 shows the molecular weight, molecular weight dispersity, and glass transition temperature of this polymer.

After cooling, remove unreacted monomers (100 mmHg, 80~
110″C) L, add toluene to this material so that the solid content is approximately 40
%, and to 100 parts of the obtained polymer was added an isocyanate compound (coronate: Nippon Polysrene Kogyo ■
, trade name) and 33 parts of ethyl acetate were added to obtain a resin composition for an adhesive.

The resulting adhesive resin composition has a thickness of approximately 50 μm after drying.
It was coated onto a polyester film using an applicator so that the film had a thickness of m, and was heated to 100°C for 2 minutes to obtain a single-sided tape. The resulting tape was tested for adhesion, cohesion, and heat resistance.

The test method is as follows.

Adhesiveness: The adhesive side of the tape is 10C1 on a surface with an inclination angle of 30 degrees.
1, roll a steel ball from above at a run-up distance of 10 cm, and measure the maximum diameter of the steel ball at which it stops on the glue surface.

Cohesiveness: 2 on a polypropylene plate degreased with alcohol.
Paste a tape cut to 0 (width)
minutes) [measuring device Niotogerafu (manufactured by Shimadzu Corporation)].

Heat resistance: Test piece for cohesiveness measurement (20aaX40ai)
Attach one end of the specimen to a stainless steel plate (with half of the test piece (20 mm x 20 layers) attached), place it in a thermostatic oven at 70°C, and attach 500 g to the other end.
Apply a load of
.

Measurement of Molecular Weight: The weight average molecular weight (Mw) and number average molecular weight ffi (Mn) were measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve.

The conditions for GPC are as follows.

Equipment used: Hitachi 635 HLC column Gelpac R440, R4
50 and R400M (both Hitachi Chemical product names)
were connected in series.

Eluent: Tetrahydrofuran Column temperature = 25°C Flow rate: 2#j! 7 minutes Detector: Differential refractometer Note that the residence time of the compound is [volume of reaction vessel (1)/(
Reaction liquid supply rate C11 minutes)]. however,
The volume of the reaction vessel refers to the maximum amount that can contain the formulation.

Measurement of glass transition temperature: Measured by the intrusion method using a thermophysical tester TMS-1 manufactured by PerkinElmer.

The test results are shown in Table 1.

Comparative Examples 1 to 3 The formulation (A) shown in Table 2 was placed in a reactor equipped with a stirrer and a cooler, heated to 90°C, and the dropwise solution (B) was added dropwise over 15 minutes to maintain the same temperature. The mixture was allowed to react for 7 hours. After cooling, the solid content was adjusted, the adhesive resin composition was adjusted, and a tape was created in the same manner as in the above examples, and the same tests were conducted. Test Results Tube 1 Table Formulation and Test Results Formulation and Test Results [Effects of the Invention] The resin composition for adhesives according to the present invention has excellent adhesion to objects to which polyolefin materials are adhered, cohesive properties, and heat resistance. ing.

Claims (1)

[Claims] 1. General formula (I): ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [In the formula, X represents a group having a copolymerizable double bond, and Y
represents a hydrolyzable group or halogen, R represents an inert monovalent organic group, n represents the number of bonds in Y and is an integer of 1 to 3, m represents the number of bonds in R and is 0, 1 or 2 and m+n is 3] 0.0
1-5% by weight, ethylenically unsaturated monomer 75-99.3
A formulation containing 9% by weight and 0.1 to 5% by weight of a monoethylenically unsaturated monomer having hydroxyl groups in the presence of 0.5 to 15% by weight of a chlorinated polyolefin resin with a chlorine content of up to 50% by weight Weight average molecular weight obtained by polymerizing below: 15
Adhesive resin containing a chlorinated polyolefin-containing polymer (A) and an isocyanate compound (B) having a molecular weight dispersity of 0,000 to 500,000, a molecular weight dispersity of 3 to 7, and a glass transition temperature of -70°C to -30°C Composition.