JP2578133B2 - Polyurethane adhesive - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention exerts excellent adhesive strength on polyurethane adhesives, more particularly on adhesion between polyvinyl chloride (PVC) and modified polyphenylene oxide (noryl). It relates to a polyurethane adhesive.

Problems to be solved by the prior art and the invention As an adhesive with excellent plasticizer resistance and heat resistance for PVC sheets or films, for example, a monomer for acrylic resin is grafted onto a thermoplastic polyester urethane rubber, which is then chlorinated rubber. Polyurethane adhesives are known which comprise an adhesive main component to which is added an isocyanate compound as a crosslinking agent (JP-A-60-92375).
Reference). However, if the other adherend adhered to PVC has a relatively low polarity such as noril, it is difficult to obtain sufficient adhesive strength.

Therefore, the present inventors have conducted intensive studies to provide an adhesive that can be applied to such low-polarity adherends, and found that a specific oligomer or polymer may be blended in place of the chlorinated rubber in the known adhesive. For example, they have found that a polyurethane adhesive having excellent plasticizer adhesion to PVC and a low-polar adherend can be obtained, and have completed the present invention.

In other words, the present invention provides (a) a thermoplastic polyester urethane rubber (hereinafter, referred to as a urethane rubber) containing at least one selected from the group consisting of acrylic acid, acrylic acid ester, methacrylic acid and methacrylic acid ester. Grafted (hereinafter referred to as graft rubber), (b) an acrylic oligomer or polymer having a number-average molecular weight of 500 to 100,000 having a functional group having an active hydrogen at a terminal or a side chain, and (c) an isocyanate compound as a crosslinking agent The present invention provides a polyurethane adhesive characterized by comprising:

The urethane rubber used in the present invention is an elastomer having a urethane bond in a molecular chain, and is usually a polybasic acid (terephthalic acid, isophthalic acid, phthalic acid, succinic acid,
Adipic acid, azelaic acid, sebacic acid, etc.) and dihydric alcohols (ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol,
Condensation reaction of diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, etc.), the resulting saturated polyester resin having a terminal hydroxyl group is reacted with its active hydrogen and a diisocyanate compound (tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene It is a linear polymer that has reacted with isocyanate groups of diisocyanate, xylylene diisocyanate, cyclohexylmethane diisocyanate, etc.) in almost equivalent amounts. Such urethane rubbers are suitable organic solvents, for example, esters (such as ethyl acetate and butyl acetate), ketones (such as methyl ethyl ketone, cyclohexanone and acetone), aromatics (such as toluene, xylene and benzene), and chlorines (such as tricrene and chloride). Dissolves easily in methylene and the like.

In the present invention, the monomer to be grafted onto the urethane rubber (hereinafter, referred to as a graft monomer) includes acrylic acid, acrylate (for example, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, isobutyl acrylate, Acrylic acid 2-
Ethoxyethyl, glycidyl acrylate, tetrahydrofurfuryl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, pentaerythitol Triacrylate, etc.), methacrylic acid and methacrylic acid esters (eg, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, t-methacrylic acid)
-Butyl, 2-ethylhexyl methacrylate, octyl methacrylate, isodecyl methacrylate, lauryl methacrylate, lauyl methacrylate-tridecyl, tridecyl methacrylate, cetyl methacrylate-stearyl,
Cetyl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, t-butylaminoethyl methacrylate, methacryl Glycidyl acid, tetrahydrofurfuryl methacrylate, etc.), and at least one selected from these groups is used. Also,
In addition to such monomers, acrylamide, acrylonitrile, acrolein, vinyl acetate, styrene, N-methylolacrylamide, vinylpyridine, maleic anhydride, vinylpyrrolidone, butadiene, and the like can be used in combination. In particular, functional groups having at least one of a hydroxyl group, a cyano group, a glycidyl group and an amino group are preferred.

In the present invention, the above-mentioned graft rubber, which is the component (a), is produced by grafting a graft monomer onto a urethane rubber by an ordinary method. For example, after dissolving the urethane rubber in an organic solvent, a radical-generating polymerization initiator (benzoyl peroxide, azobisisobutyronitrile,
60 to 10 to 10% by adding and mixing the graft monomer with kimene hydroperoxide, t-butyl hydroperoxide, potassium persulfate, ammonium persulfate, and the like.
1 hour or more while heating and refluxing at 0 ° C, preferably 2 to 4
Perform graft polymerization for hours. For such a graft,
As for the ratio of the urethane rubber and the graft monomer, it is desirable to use 10 to 70 parts of the graft monomer with respect to 100 parts (parts by weight, the same applies hereinafter) of the urethane rubber, and to graft at least 10 to 30 parts thereof. The grafted monomer is
If the amount is less than 10 parts, the adhesiveness will not be improved, and if it exceeds 30 parts, the solution viscosity may increase during polymerization, or gelation may occur. The polymerization initiator is usually used in an amount of 0.3 to 1.0 part with respect to 100 parts of the urethane rubber.If the amount is small, an excessive polymerization rate and polymerization time are required. Viscosity may increase and gelation may occur. The thus obtained graft rubber is used in a 5 to 30% solution of the organic solvent.

In the present invention, the acrylic oligomer or polymer as the component (b) has a functional group having an active hydrogen at a terminal or a side chain (for example, a hydroxyl group, a carboxyl group, an amino group, etc.), and has a number average molecular weight of 500 to 10,000.
0, preferably set to 300-15000,
For example, patents pending (Japanese Patent Application Nos. 61-208949 and 61-2093)
No. 05), the formula: Wherein R ¹ , R ² and R ₃ are the same or different and are a single bond or an alkylene group having 1 to 4 carbon atoms, R ⁴ is hydrogen or an alkyl group having 1 to 4 carbon atoms, R ⁵ is hydrogen or methyl Group,
X is an alkyloxycarbonyl group, a substituted alkyloxycarbonyl group, a cycloalkyloxycarbonyl group or a phenyl group, and n is an integer of 10,000 to 10,000], or a dihydroxyl group-containing oligomer or polymer represented by the formula: [Wherein R ^{1 to} R ⁵ , X and n are as defined above], and a dicarboxyl group-containing oligomer or polymer represented by the formula:

The oligomer or polymer of the above formulas [Ia] and [Ib] can be produced according to the following procedure.

formula: A mercaptohydroxyl compound of the formula: And a mercaptocarboxyl compound of the formula: Is photopolymerized in the absence of a solvent or in the presence of a solvent.

Examples of the above mercaptohydroxyl compound [IIa] include 1-mercapto-1,1-meth (ethane) diol (wherein, (meth) ethane refers to methane or ethane), 2-mercapto-1,2 -Propanediol,
2-mercapto-2-me (eth) tyl-1,3-propanediol [me (eth) tyl refers to methyl or ethyl, the same applies hereinafter), 3-mercapto-1,2-propanediol, 1-mercapto-2,2-propanediol, 2-mercaptome (e) tyl-1,3-propanediol, 2-mercaptome (e) tyl-2-me (e) tyl-1,3-propanediol, etc. No. Examples of the mercaptocarboxyl compound [IIb] include 2-mercapto-1,3-propanedicarboxylic acid and 2-mercapto-1,3-propanedicarboxylic acid.
Mercapto-2-me (eth) tyl-1,3-propanedicarboxylic acid [me (eth) tyl refers to methyl or ethyl, the same applies hereinafter), 2-mercapto-1,4-butanedicarboxylic acid, 2-mercapto-2-me (e) tyl-1,
4-butanedicarboxylic acid, 3-mercapto-3-me (eth) tyl-1,5-pentanedicarboxylic acid, 3-mercaptome (e) tyl-1,5-pentanedicarboxylic acid, 3-
And mercaptome (e) tyl-3-me (e) tyl-1,5-pentanedicarboxylic acid. The amount of these compounds [IIa] and [IIb] used is usually a vinyl monomer.
The amount may be selected in the range of 0.01 to 10 parts per 100 parts.

Examples of the vinyl monomer [III] include a vinyl group,
A monomer having a vinylene group or a vinylidene group,
Specifically, for example, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, amyl acrylate, hexyl acrylate,
2-ethylhexyl acrylate, cyclohexyl acrylate, n-octyl acrylate, methyl acrylate, glycidyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate,
Methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-
Ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl methacrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2, 2,3,3-
Examples thereof include tetrafluoropropyl acrylate, octafluoropentyl acrylate, and octafluoropentyl methacrylate, and one or more of these are used. If necessary, styrene, maleic anhydride, vinyl acetate, 4-META (4-methacryloxyethyl trimellitic anhydride), HEMAP (acid phosphooxyethyl methacrylate) may be used as a copolymer monomer of these vinyl monomers. , Vinyl propionate, vinyl versatate (trade name: VEOBA, manufactured by Ciel Chemical)
Vinyl chloride, acrylonitrile, acrylamide, N
-One or more of methylolacrylamide, vinylpyridine, vinylpyrrolidone, butadiene and the like may be used.

The amount of the component (b) to be used may be generally selected in the range of 0.5 to 20 parts based on 100 parts of the graft rubber of the component (a).

In the present invention, the crosslinking agent of the component (c) is an isocyanate compound used as a crosslinking agent for ordinary chloroprene solvent-based adhesives or urethane rubber adhesives, which has a high vapor pressure, low toxicity to the human body, and Any material can be used as long as it is easy, for example, triphenylmethane triisocyanate (Bayer Desmodur R, 20% methylene chloride solution), and triisocyanate phenyl thiophosphate (Bayer Desmodur RF, 20% methylene chloride solution). ,
Isocyanate compound obtained by adding trimethylolpropane to tolylene diisocyanate (Coronate L, 75% ethyl acetate solution manufactured by Nippon Polyurethane), special grade MD
I (Millionate MR manufactured by Nippon Polyurethane). Such an isocyanate compound contributes to the improvement of adhesive strength because the active hydrogen of the hydroxyl group in the molecular chain of the graft rubber (a) reacts with the isocyanate group to contribute to the improvement of the adhesive strength. The amount may be selected so as to be 3 to 50 parts with respect to 100 parts of the graft rubber of the component (a).

The polyurethane adhesive according to the present invention generally has the above (a)
An adhesive main component comprising a component and a component (b);
It is practically used in a two-part type organic solution type with a component crosslinking agent. The adhesive of the present invention is particularly useful for bonding a PVC sheet or a film to a low-polarity adherend such as Noryl, and exhibits excellent adhesive strength after heat aging. As other uses, the present invention can be applied to bonding of various plastic materials, woods and metal materials, and lamination processing of plastic films and the like.

Next, the present invention will be described more specifically with reference to Reference Examples, Examples and Comparative Examples.

Reference Example 1 (Production of acrylic oligomer) 100 g of butyl acrylate and 3-mercapto-1,2
1 g of propanediol (thioglycerol) is placed in a kolben, the system is kept at about 50 ° C. with stirring under a nitrogen atmosphere, and photopolymerization is performed while irradiating with UV (Toshiba SHL-100).
After about 6 hours, a condensable macromonomer of an acrylic oligomer is obtained. The yield determined by the weight change method (105 ° C., 4 hours) was 100%. The number average molecular weight was 1.1 × 10 ⁴ by gel permeation chromatography (GPC).

Examples 1 to 6 The urethane rubber (Pandex T5205 manufactured by Dainippon Ink and Chemicals, Inc.) having the number of parts shown in Table 1 and a graft monomer (OMA:
Octyl methacrylate, LMA: lauryl methacrylate, TM
A: tridecyl methacrylate, CMA: cetyl methacrylate,
SMA: Stearyl methacrylate, 2-HEMA: 2-hydroxyethyl methacrylate, AN: acrylonitrile), organic solvent (MEK: methyl ethyl ketone), polymerization initiator (BPO: benzoyl peroxide) were precisely weighed in a glass container in advance, The mixture was reacted for 3 hours while refluxing at 80 ° C., and the acrylic oligomer of Reference Example 1 was added and dissolved in the obtained solution to prepare an adhesive main component. Crosslinking agent (Desmo
dur R) 5 parts are blended to prepare a polyurethane adhesive.

Comparative Example 1 A polyurethane adhesive was prepared in the same manner as in Example 1 except that no acrylic oligomer was added and the amount of MEK was reduced.

Comparative Example 2 In Examples 1 to 6, the graft monomer and BPO
A polyurethane adhesive is prepared in the same manner except that the urethane rubber which is not grafted is used and the amount of MEK is reduced.

Test example Foamed PVC sheet (Sunstar Giken, Orcia) and Noril plate (Engineering Plastics, Noryl)
PX-1222) is applied at about 100 g / m ² to each of the adherends obtained in Examples 1 to 6 or Comparative Examples 1 and 2 at a thickness of 20 mm × 100 mm. After bonding, an adhesive test piece is prepared. After curing the test piece for one day, the 180 ° peel adhesive strength and the peel adhesive strength under a heating atmosphere of 110 ° C. were measured by an autograph, and a load of 100 g was applied to one end of the sheet side under the heating atmosphere. A time creep test is performed and the peel length is measured. Table 1 shows the test results.

Claims (3)

(57) [Claims] 1. A thermoplastic polyester urethane rubber having at least one selected from the group consisting of acrylic acid, acrylic acid ester, methacrylic acid and methacrylic acid ester.
A grafted species; (b) an acrylic oligomer or polymer having a number average molecular weight of 500 to 100,000 having a functional group having an active hydrogen at a terminal or a side chain; and (c) an isocyanate compound as a crosslinking agent. Polyurethane adhesive. 2. The polyurethane adhesive according to claim 1, wherein said acrylate or methacrylate includes functional groups having at least one of a hydroxyl group, a cyano group, a glycidyl group and an amino group. Agent. 3. The polyurethane adhesive according to claim 1, which is of an organic solution type.