JPS5867772A - Hot-melt adhesive - Google Patents

Abstract

PURPOSE:To prepare the titled adhesive having high peel strength at low temperature and high adhesive strength under shear at or above normal temperature, by mixing a polyolefin copolymerized with an unsaturated fatty acid, a specific tackifier, and a polyolefin elastomer at specific ratios under melting. CONSTITUTION:The objective adhesive is prepared by the melt blending of (A) 100pts.wt. of a polyolefin copolymerized with preferably 1.0-20wt% unsaturated carboxylic acid (anhydride) (preferably ethylene-acrylic acid copolymer, etc.), (B) 5-100pts.wt. of a tackifier selected from terpene-phenolic resin such as alpha-pinene-phenol copolymer, etc. or a rosin such as a gum rosin having an acid value of >=10, and (C) 30-200pts.wt. of a polyolefin elastomer such as ethylene- 1-butene copolymer, etc. EFFECT:Bonding can be carried out at low temperature under low bonding pressure. USE:Suitable for the bonding of a metal to a molded article of a rigid vinyl chloride resin.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot-melt adhesive suitable for bonding metal and plastic molded articles, particularly hard vinyl chloride resin molded articles.

There was a point. On the other hand, if an adhesive with a low softening temperature is used to improve peel adhesion strength at low temperatures, f
The shear adhesive strength of the material was severely compromised, making it impractical to use.

The present invention aims to solve one of the above problems and provide a hot-melt adhesive that can be bonded with low peeling pressure at low temperatures. 700 parts by weight of a polyolefin copolymerized with the anhydride; (b) 100 parts by weight of one or more tackifiers selected from terpene phenol resins or rosins with an acid value of 10 or more; 30-200 parts by weight of a polyolefin-based nidistomer.

The present invention will be described in detail below. In the following description, "parts" indicating a mixing ratio refer to "parts by weight."

The polyolefin copolymerized with unsaturated aliphatic carboxylic acid or its anhydride (hereinafter referred to as acid-containing polyolefin), which is the main ingredient of the adhesive of the present invention, provides basic physical properties such as cohesive force and adhesive properties during adhesion. However, while it shows good adhesion to metals, it can only provide extremely low adhesion to hard vinyl chloride resins, etc., making it unsuitable for bonding metals and plastics. .

Therefore, by adding a terpene phenol resin or a rosin with an acid value of 10 or more to the above acid-containing polyolefin, the melt viscosity of the adhesive is lowered and the affinity for synthetic resins such as vinyl chloride resin is increased to improve adhesive properties. Furthermore, by adding a polyolefin-based nidistomer, the peel adhesion strength of the adhesive at low temperatures can be improved.
It has excellent adhesion to both metals and plastics by improving shear adhesive strength at room temperature without impairing it, and
A hot-melt adhesive is obtained that exhibits little decrease in peel adhesive strength at low temperatures.

The unsaturated aliphatic carboxylic acids to be copolymerized with the polyolefin used in the present invention include acrylic acid, methacrylic acid, crotonic acid, vinyl acetic acid, maleic acid, fumaric acid, itaconic acid, mesaconic acid, citraconic acid, etc. Examples of group carboxylic anhydrides include maleic anhydride, itaconic anhydride, citraconic anhydride, etc., and these may be used alone or in combination, and the content may be O/~, ? Copolymerization or graft copolymerization is carried out in a range of 0.0% by weight, preferably 10 to 20% by weight. In addition, polyolefins include polyethylene, polypropylene, polyhapten, poly+-metallic
- Ethylene, propylene, /-ctene, damethyl-/ such as pentene, ethylene-propylene copolymer, ethylene-/-butene copolymer, propylene-/-butene copolymer, ethylene-gmethyl-l-pentene copolymer - Homopolymers such as pentene and copolymers thereof, and ethylene-vinyl acetate copolymers, ethylene-vinyl chloride copolymers, ethylene-glycidyl methacrylate copolymers, and ethylene-ethyl acrylate copolymers containing these olefins as main components , saponified ethylene vinyl acetate copolymer, etc.

Among these, ethylene/acrylic acid copolymer, ionomer, acrylic acid-modified polyethylene, maleic anhydride-modified polyethylene, maleic acid-modified polyethylene, maleic anhydride-modified ethylene-vinyl acetate copolymer, etc. can be suitably used.

Further, the terpene phenol resin is a copolymer of Guerbet/phenol and phenol, and examples thereof include α-pinene-phenol copolymer, rosin-modified phenol resin, and the like.

Examples of rosins include gum rosin, wood rosin, tall oil rosin, hydrogenated rosin, disproportionated rosin, polymerized rosin, and glycerin esters and pentaerythritol esters of these rosins.

These rosins need to have an acid value of 10 or more, and if the acid value is less than 10, the compatibility with the acid-containing polyolefin will be poor and the adhesive strength at high temperatures will decrease. The acid value is
Natural rosins (acid value ISO ~ ~ / 0), which is the highest class of ordinary rosins, can be used.

In addition, some of the terpene phenol resins or rosins used in the present invention have various softening temperatures, and may be selected as appropriate, but in order to minimize the decrease in adhesive strength at high temperatures, the ring and ball method is recommended. It is desirable to use a material with a softening temperature of 100° C. or higher.

It is known as a so-called tackifier, and the above 2
Those other than seeds have poor compatibility with acid-containing polyolefins, or have poor adhesion-improving effects even if they have good compatibility.

Or in combination of both, the amount is 5-ioo parts, preferably 70 to SO parts, per 700 parts of the acid-containing polyolefin.

If it is less than 5 parts, the adhesive force required for practical use cannot be obtained;
When the amount exceeds 0 parts, the cohesive force of the adhesive decreases, and the adhesive strength at high temperatures decreases significantly, making it no different from conventional hot-melt adhesives.

The polyolefin elastomer used in the present invention is typically a thermoplastic elastomer made by copolymerizing ethylene and α-olefin, etc.
Examples of olefins include propylene, /-butene, l-pentene, /-hexene, /-octene, /-octadecene, /-eicosene, goomethyl-/-pentene, and a small amount of non-conjugated diene, such as S-methylene-pentene. Conorbornene, S-etheridine-conorbornene, dicyclopentadiene, lI-hexadiene, etc. may be simultaneously copolymerized. For example, ethylene-butene l copolymer elastomer, ethylene-propylene copolymer elastomer, and ethylene-propylene-diene copolymer elastomer can be used. Good luck, the above ethylene α
In addition to olefin copolymer elastomers, ethylene-vinyl acetate copolymer elastomers and the like can also be used alone or in combination with other polyolefin elastomers.

The above-mentioned polyolefin elastomer has good compatibility with the acid-containing polyolefin, which is the main ingredient, and has a remarkable effect on improving the peel adhesive strength at low temperatures. Against 30~
200 parts, preferably 30 to 1 SO parts. If it is less than 30 parts, the peel adhesive strength at low temperatures will not be improved sufficiently, and if it exceeds 200 parts, the shear adhesive strength at room temperature will be impaired. In particular, a flexible polyolefin elastomer having a torsional rigidity of less than gokg/aft is suitable.

In addition to the above, other polymers, rubber components, fillers, waxes, colorants, and antioxidants can be added to the adhesive of the present invention, if necessary. In particular, when talc is added, each component can be melt-mixed with extremely good dispersibility.

In addition, in order to impart chemical resistance and corrosion resistance to metal pipes such as steel pipes, the hot-melt adhesive of the present invention can be applied to synthetic resin pipes that expand upon heating in advance for lining laminated pipes. This laminated tube is inserted into a metal tube, heated, expanded, and melted and bonded to form a synthetic resin lining.Metal tube liningMetal tubes can be manufactured by inserting the laminated tube into a metal tube, heating it, expanding it, and melting it to form a synthetic resin lining. The synthetic resin pipe will not peel or crack. Of course, in the case of a synthetic resin-lined metal tube, an outer adhesive layer having good adhesion to the metal tube and the adhesive layer may be further provided on the outer periphery of the adhesive layer of the present invention.

Example 1 Ethylene-acrylic acid copolymer i as polyolefin
oo parts by weight, 3 to 20 parts of α-pinene phenol as a tackifier as shown in Experiment &/~S in Table 1, SQ parts of ethylene=7-butene copolymer as a polyolefin elastomer, This blended composition was melt-mixed using a single screw extruder to produce an adhesive film with a thickness of about /SOμ.

Next, according to FIG. 1, which shows a cross-sectional view of a sample for measuring shear adhesive strength, the adhesive film was cut into a square with an angle of Board / and degreased thickness 0.71111111
The adhesive film 3 was sandwiched between a cold-rolled steel plate having a length of 73 rran and a length of 10 tran, and was heated at 120° C. for 2 minutes.
Both plates are heated and melted and bonded at a pressure of Iof/-/crfl,
This sample was applied to a tensile tester at 20C1 at a tensile rate of 0.
．． ! Table 1 shows the results of measuring the shear bond strength parallel to the adhesive surface at btm 7 minutes.

In addition, 42 shows a cross-sectional view of a sample for measuring peel adhesion strength.
According to the diagram, a 15 square adhesive film 3 similar to the above was sandwiched between the polyvinyl chloride plate and the cold rolled steel plate, and bonded at 720°C for 1 hour with a pressure of 10 of/cr/l. Table 1 shows the results of measuring the peel adhesion strength when this was put on a tensile test machine and pulled in a direction perpendicular to the adhesive surface at a tensile speed of 200 III m for 7 minutes in an atmosphere of 20°C and -70°C. show.

As shown in Table 1, No. 1il, even in an experiment where the amount of α-pinene phenol added to K and adhesive 4 resin was less than 3 parts, the amount exceeded 100@! However, shear adhesive strength and peel adhesive strength decrease.

Ethylene-acrylic acid copolymer 1 as a practical copolyolefin
00w6, α-pinenephenol 30 as a tackifier
Part, ethylene-1 as polyolefin elastomer
- Experiments in Table 1 of Puteshi Kyojuku Body/O-Js as shown in I66 to IO.

This blended composition was melt-mixed using a single-screw extruder to produce an adhesive film with a thickness of 10 μm.

Next, the shear adhesive strength and peel adhesive strength of the obtained film were measured in the same manner as in Example 1, and the results are shown in Table 2.

As shown in Table 1, when the amount of ethylene-l-butene copolymer added is less than JO@, the shear adhesive strength is high, but the peel adhesive strength is low at both 2θ℃ and -70℃. small. On the other hand, if more than 2 SO parts are added, the shear adhesive strength will decrease.

Example 3 The compositions shown in Experiment 4G, //~/B in Table 3 were formed into a film in the same manner as in Example/, and the shear adhesive strength and peel adhesive strength were measured in the same manner as in Example 1. It is shown in Table 3.

In Experimental Pot/3 in Table 3, the acid value of the glycerin ester of the hydrogenated rosin added is 30, which is lower than 10, so both pre-adhesive strength and peel adhesive strength are low, making it impractical.
Experiment &//, /2, /Goo/6 are formulations of the present invention and have excellent shear adhesion strength and peel adhesion strength.

Example 1 The composition shown in Experimental House No. 77-2 B in Table 1 was melt-mixed, and the outer circumferential surface hK of a thermally expandable polyvinyl chloride pipe (for size soA, length s g s o wx ) was coated with a cloth. Extrusion coated from Herado die. The thickness of the adhesive is 75
It was set as μ. Carbon steel pipe (size soA, length sso
.

rrrIn) and heat lined. The heat resistance and cold resistance of the thus obtained lined steel pipe were evaluated using the following methods, and the results are shown in Table 1. For comparison, the results of evaluating conventional lined steel pipes manufactured in the same manner as in Experiment A and 7 to λ6, except that a normal solvent-based adhesive was applied instead of the molten adhesive, are shown in Experiment A core. .

Heat resistance: A 1,000-piece sample was cut from any location on the lining pipe, and a 10-cycle cold/heat cycle test was performed, including immersion in GOC hot water for 2 hours and immersion in 20°C water for 2 hours/cycle. Ta. After that, the inner surface of the sample was visually observed to check for the presence of small protrusions on the inner surface due to peeling of the adhesive, and also to determine the amount by which the end of the PVC pipe shrank from the end of the metal pipe. After measuring, 5 test pieces with a width of 20 rKIn were cut out at uniform intervals for measuring adhesive strength, and the punching strength was measured at 20°C based on JWWA-//A (Japan Water Works Association Standards) to determine the heat resistance. did. Note that the punching strength of the lining pipe before the test was measured in the same manner as the initial strength.

Cold resistance: Cut a sample from the lined tube with a length of -250 mm, leave it in an atmosphere of θ℃ for 10 hours or more, and then drop it from a height of 20 m/m to remove the inner surface of the sample. The cherry blossoms were inspected with the naked eye, and if cracks appeared in the PVC pipe, it was judged as a failure, and if there were no cracks, it was judged as a pass.

As shown in Table 7, in experiments A and S using adhesives without the addition of polyolefin elastomers, the heat resistance was good, but the cold resistance was poor, and the internal polyvinyl chloride pipes cracked due to impact. On the other hand, in Jikken-ya 2A, in which more than 200 parts by weight was added, the heat resistance was extremely poor, the adhesive strength decreased, the amount of shrinkage was too high, and small protrusions caused by peeling occurred frequently. In contrast, Birth Experiment A/7-2'l using the adhesive composition of the present invention had good heat resistance and cold resistance, compared to conventional Experiment A2 using a solvent-based adhesive. It was also excellent compared to the example above.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a sample for measuring shear adhesive strength, and FIG. 42 is a sectional view of a sample for measuring peel adhesive strength. /...Hard polyvinyl chloride plate...Cold rolled steel plate 3...Adhesive fill l. Man J Shinakou 2 Figure

Claims (1)

[Claims] (a) IOO parts by weight of polyolefin copolymerized with unsaturated aliphatic carboxylic acid or its anhydride, and (b) 7 or 2 or more types of adhesive selected from terpene phenol resins or rosins with an acid value of 10 or more. Imparting agent! -10θ weight part and (e) polyolefin elastomer 3θ~20
A hot-melt adhesive formed by melt-mixing 0 parts by weight.