JPH0373595B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot melt adhesive having excellent low-temperature melting properties, heat resistance, and adhesion to polyolefin substrates. Traditionally, hot melts have been made using base polymers such as ethylene vinyl acetate and polyamide, tackifiers such as rosin and petroleum resins, and viscosity-lowering agents such as various waxes and low-polymerization polyolefin resins, or oils and plasticizers. Softening agents such as
It was used as an adhesive by adding it to achieve low-temperature melting. In particular, for adhesion of polyolefin sheets that have poor heat resistance and poor wettability, low-temperature meltability and low viscosity are required, and the selection of waxes was an important factor. In other words, although ordinary waxes have good adhesive workability, they have poor adhesive strength after solidification.
Also, softeners such as oil and plasticizers caused a decrease in heat resistance. An object of the present invention is to provide a hot melt adhesive that has excellent adhesive workability, heat resistance, and adhesion to polyolefin base materials. The present invention relates to a hot melt adhesive comprising a thermoplastic rubber mixed with a tackifier and an oxidized polyolefin wax. In the present invention, thermoplastic rubbers include styrene-isoprene-styrene block copolymers (SIS), styrene-butadiene-styrene block copolymers (SBS), and styrene-ethylene-butylene-styrene block copolymers (SEBS) with a styrene content of 10 to 10. Elongation rate 500~ with 50 parts copolymer
It is a 1500% rubber-like elastic material, and is usually used as a modifying material for plastics, vulcanized rubber, or asphalt. Commercially available products include Califrex TR, Clayton G (manufactured by Schiel Chemical Co., Ltd.), and Tuftrene, Examples include Solprene and Asaprene (manufactured by Asahi Kasei Corporation). Among these, sutin content
SBS with a linear structure of 25-30 parts and an elongation rate of 700-1000%
is optimal in terms of adhesion. Next, as the tackifier, commercially available tackifiers such as hydrogenated rosin, hydrogenated rosin ester, polymerized rosin, polymerized rosin ester, _C3-5 petroleum resin, and terpene phenol resin can be used. Among these, polymerized rosin ester is most suitable in terms of adhesiveness. In addition, oxidized polyolefin wax refers to polyethylene oxide or polypropylene oxide, which is obtained by air oxidation or thermal decomposition of polyolefin wax with a low degree of polymerization that is produced when producing polyethylene resin or polypropylene resin, and has carboxyl groups. , an oxidized polyolefin wax with an acid value of 2 to 60 and a softening point of 100 to 150°C due to the presence of carbonyl groups, and an oxidized polyolefin wax with an acid value of 30 to 120 and a softening point of 100 to 120°C obtained by copolymerizing ethylene and acrylic acid. Also includes ethylene acrylic acid copolymer. Among these, acid value 2-15, softening point 100
Polypropylene oxide at ~150°C is optimal in terms of adhesion and flexibility. Next is the mixing ratio of thermoplastic rubber, tackifier, and oxidized polyolefin wax.
150 parts, preferably 50 to 100 parts, and 10 to 50 parts, preferably 15 to 30 parts of oxidized polyolefin wax are suitable in terms of meltability, viscosity, solidification and adhesion to polyolefin sheets. . Further, appropriate amounts of fillers (calcium carbonate, talc, clay, etc.), pigments (coloring pigments such as titanium oxide, carbon, etc.), anti-aging agents (phenol-based, amine-based, etc.), etc. may be added as necessary. To produce the hot melt adhesive of the present invention,
mixer, which may be carried out according to the usual methods;
The mixture may be heated and mixed using a mixer such as a kneader or a mixing roll under normal conditions. The present invention uses a combination of a thermoplastic rubber made of a block copolymer such as SIS or SBS and an oxidized polyolefin wax such as polyethylene oxide or polypropylene oxide to raise the melting temperature to a level that does not cause the polyolefin sheet base material to soften and deform. It improves wetting to adherends and enables adhesion to polyolefin sheet substrates. That is,
Among waxes that are effective for lowering viscosity, controlling solidification temperature, improving heat resistance, etc., oxidized polyolefin waxes that contain polar groups such as carboxyl or carbonyl groups are polyolefin waxes that cannot be bonded with ordinary waxes. It is presumed that this enables adhesion to the sheet base material. Furthermore, it is presumed that the flexibility, viscoelasticity, and high elongation rate peculiar to block copolymers are effective in adhesion to flexible polyolefin sheets and in heat-resistant creep properties. As described above, the hot melt adhesive of the present invention has a low solidification temperature, low viscosity, and excellent heat-resistant creep properties, and is useful as a hot melt adhesive for polyolefin sheets. Next, the present invention will be explained by examples. Examples 1 and 2, Comparative Examples 1 and 2 100 parts by weight of styrene-butadiene-styrene block polymer (SBS) (Califlex TR1102: manufactured by Ciel Chemical Co., Ltd.) as a thermoplastic rubber, and rosin ester (Pentaline A:
100 parts by weight of polyethylene oxide with an acid value of 20 and a softening point of 115°C (Example 1), polypropylene oxide with an acid value of 3.5 and a softening point of 145°C (Example 2), and microorganisms with a melting point of 85°C. 20 parts by weight of wax (Comparative Example 1) and polyethylene wax (Comparative Example 2) with a softening point of 108°C were heated and mixed to form the hot melt adhesives of Examples 1 and 2 and Comparative Examples 1 and 2, and the mixture was heated at 208°C. Table 1 shows the results of measuring the viscosity at 0.8 mm thick polypropylene sheets, the T-peel adhesion strength at 0°C, 25°C, and 50°C, and the shear creep test at 70°C. 【table】

Claims (1)

[Claims] 1. A hot melt adhesive comprising 100 parts by weight of thermoplastic rubber mixed with 30 to 150 parts by weight of a tackifier and 10 to 50 parts by weight of an oxidized polyolefin wax.