JPH01144483A - hot melt adhesive composition - Google Patents

Abstract

PURPOSE:To provide the title composition giving excellent adhesive force for sparingly adhesive polyolefin plastics such as polypropylene and ethylene- propylene copolymers, comprising a styrene thermoplastic rubber, tackifying resin, process oil and low-molecular weight polypropylene. CONSTITUTION:The objective composition comprising (A) pref. 15-45wt.% of a styrene thermoplastic rubber (e.g., styrene-isoprene-styrene block copolymer), (B) pref, 30-60wt.% of a tackifying resin (e.g., 5-C petroleum resin, (C) pref. 10-35wt.% of a process oil (pref. naphthene oil or paraffin oil), and (D) pref. 10-30wt.% of a low-molecular weight polypropylene.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides excellent adhesion to difficult-to-adhesion polyolefin plastics such as polypropylene, ethylene, and propylene copolymers, which are widely used in various industrial fields. The present invention relates to a hot melt adhesive composition with high strength.

[Conventional technology and its problems]

BACKGROUND ART Polyolefin plastics such as polypropylene have been known to be difficult to adhere to due to the nonpolar and crystalline nature of their surfaces, and various methods of adhering these materials have been studied. For example, there are (1) a method in which identical materials are made to adhere to each other by heat using ultrasonic waves or the like, and (2) a method in which the adhesive strength is increased by treating the surface of the materials. However, method (+) is not only suitable only for bonding similar materials, but also has the disadvantage of damaging the material itself due to thermal deformation, and method (2) increases the number of steps for bonding and reduces the adhesive performance itself. The drawback is that it cannot be satisfied.

Also, Special Publication No. 47-21720, Special Publication No. 48-9932
et al. have proposed an adhesive consisting of a styrene-isoprene block copolymer, a tackifying resin, and a process oil, but due to the insufficient cohesive force of the adhesive p, the adhesive strength, especially heat resistance, may be insufficient, and the adhesive strength may be insufficient. There are problems such as staining of the adhesive material due to the extrusion of the agent, and this is unsatisfactory.

Furthermore, in JP-A No. 62-48779, copolymers obtained by hydrogenating styrene-isoprene-styrene block copolymers or styrene-butadiene-styrene block copolymers, hydrocarbon resins solid at room temperature, waxes and number average There have been proposals for compositions of hydrocarbon-based synthetic rubber having a molecular weight of 300 or more and a pour point of 120° C. or less, but these are unsatisfactory in terms of adhesive heat resistance and adhesion cold resistance.

The present invention provides an adhesive composition that has excellent adhesive performance, that is, heat-resistant adhesive strength at 100°C and cold-resistant adhesive strength at -20°C, for polyolefin plastics that are considered extremely difficult to adhere to. The purpose is to provide

[Means to solve the problem]

The present invention provides an excellent adhesive composition free from the above problems, and is a hot melt adhesive composition characterized by containing the following four components.

(A) Styrenic thermoplastic rubber, (b) tackifying resin; (C) process oil, ([1) Low molecular weight polypropylene.

Thermoplastic rubber in the present invention means a polymer that has plasticity and can be molded into any shape in a high temperature range and has rubber-like elasticity in a normal temperature range. Brene-styrene block copolymer, styrene-butadiene-styrene block copolymer,
There are styrene-oleph, in-styrene block copolymers, etc., which can be used alone or in combination of two or more. The amount of the above-mentioned styrenic thermoplastic rubber used is not limited, but if it is too small or too large, the balance between cohesive force and wettability of the composition cannot be maintained. It is used in an amount of 10 to 50% by weight, preferably 15 to 45% by weight.

The tackifying resin in the present invention is used to improve adhesive properties, and specific examples thereof include C-5 petroleum resin, C-9 petroleum resin, terpene resin, rosin and rosin derivatives, and respective water-based resins. Added petroleum resins, etc., are used alone or in combination of two or more types, and are usually 20 to 70% by weight, preferably 30 to 6% by weight in the total composition.
It is used in a range of 0% by weight.

Process oils in the present invention include naphthenic oils, paraffin oils, aroma oils, etc.
Naphthenic oils and paraffinic oils are particularly preferably used. The above process oil is essential for improving cold-resistant adhesive properties, and is usually used alone or in combination of two or more in the total composition in an amount of 5 to 40% by weight, preferably 10 to 35% by weight.

The low molecular weight polypropylene in the present invention is generally obtained by thermally or oxidatively decomposing polypropylene;
It is also a low-polymerization product of propylene, which is essential for improving heat-resistant adhesion. The above-mentioned low molecular weight polypropylene is generally used in the total composition in an amount of 5 to 35% by weight, preferably 10 to 30% by weight.

In the present invention, other additives other than those mentioned above can be used within a range that does not impair the purpose of the present invention. Examples of such additives include plasticizers such as liquid polybutene, liquid polyisoprene, and liquid polybutadiene, various waxes such as paraffin wax, microcrystalline wax, and polyethylene wax, ethylene-vinyl acetate copolymers, and ethylene-vinyl acetate copolymers.
Examples include thermoplastic resins such as ethyl acrylate copolymers, known antioxidants, colorants, fillers, and the like.

To produce the composition of the present invention, the above raw materials are in a molten state (
They may be mixed by a conventional method at a temperature of 120 to 200°C.

[Effect]

The hot melt adhesive composition containing four components of the present invention has the effect of providing an adhesive with excellent adhesion performance to polyolefin plastics, which are difficult to adhere to, due to the coexistence of the four components. In particular, it has heat-resistant adhesion at 100°C and cold-resistant adhesion at -20'C, and this excellent effect of the present invention was achieved for the first time by using four components together. be.

[Example of ability]

Evaluation method/Softening point - Ring and ball method Measured according to JIS-2207.

- Melt viscosity - 180° according to JAI-7-1980
C and measured using a B-type rotational viscometer.

・Adhesive strength: A hot melt adhesive melted at 180°C was applied to 300 μ thick polypropylene at a coating amount of 5 g/rtf, and a 25 m wide test piece was created by hand pressure bonding, and the T-peel strength was determined. It was measured. The measurement temperatures were -20°C and 20'C. The tensile speed was measured at 200 mm/win.

・Heat-resistant adhesion ---A hot melt adhesive melted at 180'C is bonded to a 300μ thick polypropylene with an area of 25
A test piece was prepared by applying the coating in mm x 25+ am, and was then manually crimped to measure the heat-resistant shear retention force. 2 on the above adhesive test piece
With a load of 0.00 g applied, the ambient temperature is increased successively from 40°C by 5°C every 30 minutes, and the maximum temperature that does not cause any displacement or peeling of the bonded portion is indicated.

Examples 1 to 5 As the styrene thermoplastic rubber, a styrene-isoprene-styrene block copolymer (Califlex TR-1117, manufactured by Shell Chemical) or a styrene-olefin-styrene block copolymer (Clayton G-1657, manufactured by Shell Chemical) was used. , C-5 petroleum resin (Escolettes 4401 manufactured by Exxon Chemical Co., Ltd.) as a tackifier.
, terpene resin (YS resin To-115 made by cheap crude oil)
), C-9 hydrogenated petroleum (Arakawa Chemical Alcon p-1
15) or rosin derivative (Super Ester A-115 manufactured by Arakawa Chemical), naphthenic oil (Shell Flex 371 manufactured by Shell Chemical) as a process oil
JY) or paraffin oil (Idemitsu Process Oil PS32), low molecular weight polypropylene (Viscol 550P manufactured by Sanyo Kasei) and an antioxidant (Irganox 1010 manufactured by Ciba Geigy) are heated and melted to form a true melt adhesive composition. Obtained.

Their compositions and physical properties are shown in Table 1.

Comparative example! Liquid polybutene (Idemitsu Petrochemical Polybutene 2000H) was used instead of naphthenic oil.

The composition and physical properties are shown in Table 1.

Comparative Example 2 Polyethylene wax (Hiwax 110P manufactured by Mitsui Petrochemicals) was used instead of low molecular weight polypropylene. The composition and physical properties are shown in Table 1.

Comparative Example 3 Polyisobutylene (Tetrax 4T, manufactured by Nippon Petrochemical) was used instead of paraffin oil, and microcrystalline wax (Microwax 180, manufactured by Mopil) was used instead of low molecular weight polypropylene. The composition and physical properties are shown in Table 1.

〔Effect of the invention〕

The adhesive composition of the present invention can be used to bond structures made of olefin plastic materials, which have been difficult to achieve with conventional hot melt adhesives, such as assembling and bonding polypropylene containers, attaching polyethylene parts to polypropylene containers, etc. It is possible to provide a hot melt adhesive having excellent adhesive performance, particularly heat-resistant adhesiveness and cold-resistant adhesiveness, and it is possible to exhibit excellent effects of being effectively used in a wide variety of industrial fields.

Patent applicant: Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] A hot melt adhesive composition characterized by containing the following four components. (A) Styrenic thermoplastic rubber, (b) Tackifier resin, (C) Process oil, (D) Low molecular weight polypropylene.