JPS61200185A - Pressure-sensitive adhesive - Google Patents

Abstract

PURPOSE:To obtain a pressure-sensitive adhesive suitable for coating on the surface of polyolefin-based cured rubber or resin, by blending an urethane and copolymer from specific (meth)acrylic derivative and active hydrogen-contg. compound. CONSTITUTION:The objective pressure-sensitive adhesive can be obtained by blending (A) a copolymer from (i) <=13C (meth) acrylic derivative (e.g., n-butyl acrylate) and (ii) active hydrogen-contg. compound (e.g., maleic anhydride) and (B) an urethane [pref. NCO group-terminated one derived from reaction between isocyanate and a blend of polyol (P) and triethanolamine (T) with a molar ratio (P)/(T) 1/0.05-2.0] pref. in a weight ratio (on a solid basis) (A)/(B) 100/0.007-500.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to an adhesive that is applied to the surface of various substrates made of polyolefin resin or polyolefin vulcanized rubber.

(Prior art) Ethylene-propylene-diene ternary copolymer rubber (EPD
Polyolefin vulcanized rubber such as M) and ethylene-propylene copolymer comb (EPM) or polypropylene (
Polyolefin synthetic resins such as PP) and polyethylene (PE) are natural rubber (NR), styrene-butadiene copolymer rubber (SBR), polybutadiene rubber (BR), isobutylene-isoprene copolymer rubber (IIR), and Chloroprene rubber (CR), acrylonitrile-butadiene copolymer rubber (NBR), polyisoprene rubber (I
Weather resistance and aging resistance compared to synthetic rubber such as R) or synthetic resins such as ABS resin, polystyrene resin (PS), acrylonitrile-styrene copolymer resin (AS), and ethylene-vinyl acetate copolymer resin (EVA). It exhibits outstanding performance in terms of durability and ozone resistance, and also has an operating temperature range of 150°C.
These rubbers and synthetic resins have excellent characteristics such as a wide temperature range of 150°C to 150°C, so they are now used in many fields.

(Problems to be Solved by the Invention) However, polyolefin vulcanized rubbers such as EPDM and EPM, and polyolefin resins such as PP and PR do not contain polar groups in the main chain of their molecules. Even if an adhesive is applied to the adhesive, the resulting coating film is likely to peel off, making it extremely difficult for these polyolefin rubbers and resins to adhere to each other, to rubber and resin, or to other materials such as metals and plastics. This is the current situation.

A number of countermeasures have been attempted to address these drawbacks, but no satisfactory solution has yet been found.

In order to solve the above-mentioned problems, the present inventor has conducted many years of research into adhesives for polyolefin vulcanized rubber and polyolefin resins, and as a result, has developed an adhesive that has sufficient adhesion to these base materials. I came to find out.

Structure of the Invention (Means for Solving Problems) The present inventor has developed an acrylic derivative or methacrylic derivative having 18 or less carbon atoms and an active hydrogen-containing compound as an adhesive to be applied to the surface of polyolefin vulcanized rubber or resin. We attempted to solve the above problems by devising an adhesive made by mixing a copolymer of urethane with urethane.

(Function) This adhesive, which is made by mixing urethane with a copolymer of an acrylic or methacrylic derivative having 18 or less carbon atoms and an active hydrogen-containing compound, is highly reactive because it contains a polar group.

Therefore, if this adhesive is applied to polyolefin-based vulcanized rubber or resin and used for adhesion between polyolefins or other materials such as metals and plastics, strong adhesion can be obtained.

(Example) Hereinafter, this adhesive will be explained by giving examples.

Acrylic derivatives having 18 or fewer carbon atoms include acrylic acid,
Methyl acrylate, ethyl acrylate, n-butyl acrylate, 1so-butyl acrylate, 2-ethylhexyl acrylate, isodecyl acrylate, lauryl acrylate, C52-CI3 mixed alkyl acrylate, stearyl acrylate and q0-q8/
Examples include kongo alkyl J rare acrylate.

In addition to methacrylic acid, methacrylic derivatives having 18 or fewer carbon atoms include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, tso-butyl methacrylate, 2-ethylhexyl methacrylate, isodecyl methacrylate, lauryl methacrylate, (~q
, mixed alkyl methacrylate, stearyl methacrylate, C12-mixed alkyl methacrylate, and the like.

Active hydrogen-containing compounds include acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, and maleic acid, maleic anhydride, fumaric acid, and citraconic acid. , citraconic anhydride, itaconic acid, and itaconic anhydride.

An active hydrogen-containing acrylic adhesive can be obtained by copolymerizing the above-mentioned methacrylic derivative or acrylic derivative having 18 or less carbon atoms with an active hydrogen-containing compound by a conventional method.

Further, at this time, the methacrylic derivative and the acrylic derivative may be mixed and copolymerized with the active hydrogen-containing compound.

Next, urethane is obtained by reacting a mixture of polyol and triethanolamine with polyisocyanate, and has an NCO group at the end.

A small number of polyols (polyether polyols and polyester polyols with trifunctional groups are used).

Examples of polyether polyols include diols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly(propylene oxide-ethylene oxide) glycol, propylene oxide-glycerin reactants, propylene oxide-trimethylolpropane reactants, etc. be.

Examples of polyester polyols include adipic acid esters such as polyethylene adipate, polybutylene adipate, and polyethylene butylene adipate.

In addition, polyisocyanates include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hydrogenated 4,4'-diphenylmethane diisocyanate, 1,5
- naphthalene diisocyanate, xylene diisocyanate, hydrogenated xylene diisocyanate, isophorone diisocyanate, 1°6-hexamethylene diisocyanate, etc.

In order to prepare the above urethane, the above polyol, isocyanate and triethanolamine dissolved in a solvent such as trichlorethylene may be reacted in a dry nitrogen gas at 80°C for 3 hours using a conventional method. It is possible to obtain urethanes with groups.

The blending ratio of polyol and polyisocyanate in this reaction is preferably OH/NCO=1/1°5-7 in terms of equivalent ratio.

If the amount of NCO is less than 5 equivalents, the adhesive strength will decrease, and even if 7 equivalents or more is added, the adhesive strength will not improve.

In addition, the blending ratio of polyol and triethanolamine is 0.0 triethanolamine per 1 mole of polyol.
It is 5 to 2 moles.

The adhesive of the present invention is a mixture of the urethane and the active hydrogen-containing acrylic adhesive, which is a copolymer of the methacrylic derivative and/or acrylic derivative and the active hydrogen-containing compound, in a solvent.

The mixing ratio of these is 0°007 to 5% urethane solid content to 100 parts by weight solid content of the active hydrogen-containing acrylic adhesive.
The urethane solid content is preferably 0.007 to 100 parts by weight, and more preferably 0.007 to 100 parts by weight.

If the urethane solid content is less than 0.007 parts by weight, the adhesive strength will decrease, and if it is more than 500 parts by weight, the adhesive strength will not improve and the curing time will become longer.

The solvents used during mixing include aromatic hydrocarbons such as benzene, toluene, and xylene, ketones such as methyl ethyl ketone, methyl isopropyl ketone, and methyl isobutyl ketone, and acetic esters such as methyl acetate, ethyl acetate, isopropyl acetate, and isobutyl acetate. Alternatively, it is a saturated hydrocarbon such as n-hexane or cyclohexane.

To apply the adhesive with the above composition to the surface of various base materials made of polyolefin resin or polyolefin vulcanized rubber, it is sufficient to use ordinary painting methods such as dipping, spraying, and brushing, and special equipment is required. is not necessary.

Further, prior to applying the adhesive, the base material may be subjected to corona discharge treatment or plasma treatment to activate its surface.

As an example of this corona discharge treatment, power = 1 kW, electrode: knife type, electrode length: 300 m, electrode-substrate distance: 1
This can be done under Tsuru's conditions.

Next, the adhesive strength of the adhesive of the present invention was investigated using the following examples.

First, the EPDM composition shown in Table 1 was vulcanized at 160° C. for 30 minutes to prepare a test piece with a thickness of 2 mm.

(Hereinafter, all parts in the table are parts by weight.)

Next, an adhesive consisting of a mixture of an active hydrogen-containing acrylic adhesive and urethane was applied to the surface of this test piece, and
Dry for 2 minutes at °C.

The test pieces coated with this adhesive were pasted together and left at room temperature for 20 days, and then a shear test was conducted at a tensile rate of 30'mm/min.

Table 2 shows the composition of the urethane in the adhesive used, the mixing ratio of urethane and acrylic adhesive, and the shear strength.

The acrylic adhesives used in Examples 1 to 15 were all made by copolymerizing maleic anhydride and n-butyl acrylate in a mixed solvent of toluene/cyclohexane/ethyl acetate = 1/1/1. 20-25, solid content 37
% active hydrogen-containing acrylic adhesive.

Further, the urethane in each example was prepared by appropriately changing the mixing ratio of polyol and triethanolamine, the type of isocyanate, etc.

For example, the urethane of Example-1 was dissolved in polypropylene glycol (molecular weight = 300
0) Add 0.7 mol of triethanolamine to 1 mol and further add 4.4' so that OH/NC0=1/4.
-Diphenylmethane diisocyanate was reacted in dry nitrogen gas at 80°C for 3 hours, and 19 parts of toluene was added to 1 part of the resulting solution (solid content 83%).

In addition, the adhesive of Example-1 was the above acrylic adhesive 100.
1 part of this urethane.

In addition, Comparative Example 1 in Table 2 is a case where only an acrylic adhesive was used, and its shear strength was almost 0.

In addition, the curing time of the adhesives of Comparative Examples 2 and 3 was too long, and the shear strength could not be measured.

The results of this shear test show that the adhesives of Examples 1 to 15 have extremely strong adhesive strength.

Next, an embodiment in which the adhesive of the present invention is applied to a mounting structure for an automobile molding will be described with reference to the drawings.

The car body is equipped with a molding made of vinyl chloride resin that serves both as protection and decoration.

As shown in FIG. 2, this resin molding 2 is attached to an automobile body 1 via a double-sided adhesive tape 4.

This double-sided adhesive tape 4 has a base material 5 made of sponge, nonwoven fabric, film, paper, etc. formed on a thin plate of material such as acrylic, polyethylene, or chloroprene, and acrylic adhesive such as butylene acrylate, butyl methacrylate, 2-ethylhexyl acrylate, etc. It is coated with adhesive 6. However, these acrylic adhesives6
It has been pointed out that the molding 2 may peel off from the body 1 during long-term use because the adhesion of the molding 2 is not sufficient.

Therefore, the present inventor devised a means for using the adhesive of the present invention in the above-mentioned molding mounting structure, and conducted the following tests in order to investigate the effect thereof.

〔Test method〕

A sponge made of a 5x polyethylene foam was used as a base material, and an adhesive made of the active hydrogen-containing acrylic adhesive and urethane was applied to the surface of the sponge.

Next, this base material was attached to an acrylic-coated iron plate and left for 24 hours, and then the shear strength was examined at a tensile rate of 301/min.

Table 3 shows the composition of the adhesive and the shear strength of each. In addition, Comparative Example 4 in Table 3 uses an acrylic adhesive alone, and its shear strength was approximately O.

The curing time of the adhesives of Comparative Examples 5 and 6 was so long that the shear strength could not be measured.

In addition, Comparative Example-7 is a commercially available double-sided adhesive tape (Nitto Denko #
500) was used.

From the results of the shear test shown in Table 3, it was found that the adhesives of Examples 16 to 30 all had extremely strong adhesion and exhibited sufficient effects when used in the mounting structure of the molding.

FIG. 1 shows an adhesive 3 of the present invention applied to a base material 5 of a double-sided adhesive tape 4.
This is the mounting structure of the molding 2 coated with.

At this time, instead of the adhesive material 3, a chloroprene-based adhesive, a urethane-based adhesive, or the like may be used on the molding 2 side of the base material 5.

Furthermore, the mounting structure using this adhesive 3 can be applied not only to attaching the molding 2 to the automobile body 1, but also generally when attaching a synthetic resin material to metal or other members via double-sided adhesive tape 4. Can be done.

Effects of the Invention As detailed above, the adhesive of the present invention can be applied to polyolefin-based vulcanized rubber or resin and used for adhesion between polyolefins or with metals or various synthetic resins. It is an excellent invention that can be used for a wide range of purposes, and has the effect of achieving adhesion.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing a molding mounting structure using the adhesive of the present invention, and FIG. 2 is a sectional view showing a conventional molding mounting structure. 1...Automobile body, 2...Mall, 3...Adhesive.

Claims (1)

[Scope of Claims] 1. An adhesive comprising a copolymer of an acrylic or methacrylic derivative having 18 or less carbon atoms and an active hydrogen-containing compound mixed with urethane. 2. The solid content weight ratio of the copolymer and urethane is 100
/0.007-500. 3. A patent claim in which the urethane is obtained by reacting a mixture of polyol/triethanolamine = 1/0.05 to 2.0 (molar ratio) with polyisocyanate and has an NCO group at the end. The pressure-sensitive adhesive according to item 1 or 2.