JPH1046121A - Hot-melt adhesive for polypropylene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot-melt adhesive for polypropylene resins which can be used for bonding polypropylene to polypropylene and to other materials such as wood, ceramics, or metal and can be molded into a film. SOLUTION: This adhesive mainly comprises 70-95wt.% α-olefin copolymer and 5-30wt.% tackifier. An esp. pref. example of the copolymer is one which has ethylene units together with other monomer units. A thermally bondable polypropylene laminate film is obtd. by forming a layer of the adhesive on one side of a polypropylene film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot melt adhesive, and more particularly to a hot melt adhesive for polypropylene.

[0002]

2. Description of the Related Art In recent years, hot-melt bonding has been achieved due to its features such as simplicity of the bonding process, ease of handling, quality stability of long-term storage, and the elimination of solvents harmful to workers and the environment. Agents are being developed for a wide variety of products and are becoming widely used.

[0003] However, despite the emergence of various hot melt adhesives, few hot melt adhesives can strongly adhere polypropylene. When a non-polar polypropylene is bonded to a polar material, such as wood, a hot melt adhesive having excellent adhesive performance to both materials is still limited.

A conventional hot melt adhesive is generally in the form of a stick. When bonding is performed using the stick, the molten hot melt adhesive is melted by a method using a stick gun or an open flame. The bonding method is limited to a bonding method applied to a portion of a material to be bonded. In addition, if a hot melt adhesive laminated polypropylene film obtained by laminating a hot melt adhesive on a polypropylene film is obtained, it is extremely convenient for bonding or laminating the polypropylene film to various materials, but the conventional hot melt adhesive is Due to the low melt viscosity, it was difficult to laminate on a polypropylene film using an extruder with good workability. Even if it could be formed into a film by another method, it could not be rolled up or stored because of its strong blocking property.

[0005] Further, the hot melt adhesives conventionally obtained have low softening points and low melt viscosities, and thus have limited applications such as poor heat resistance and poor weather resistance. For example, it could not be applied to plywood used outdoors. In producing a hot melt adhesive, the workability of the conventional hot melt adhesive was inferior because it was prepared by a batch-type melt mixing method.

[0006]

SUMMARY OF THE INVENTION The present invention provides a hot melt adhesive for polypropylene resin which can be applied to bond polypropylene to each other, and further to polypropylene and other materials, especially polar materials such as wood, ceramic, metal and the like. It is intended to be. Another object of the present invention is to provide the above-mentioned hot melt adhesive formed in a film shape. Still another object of the present invention is to provide a heat-bondable polypropylene laminated film in which a hot melt adhesive is laminated and adhered to one side of a polypropylene film.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a hot-melt adhesive for polypropylene resin containing 70 to 95% by weight of an α-olefin copolymer and 5 to 30% by weight of a tackifier. The present invention also relates to the hot melt adhesive for polypropylene resin formed in a film shape.
Further, the present invention relates to a heat-fusible polypropylene laminated film in which the above-mentioned hot melt adhesive is laminated and adhered to one surface of a polypropylene film.

[0008] The hot melt adhesive for polypropylene resin of the present invention has the following characteristics which could not be obtained conventionally: 1) It is possible to strongly bond polypropylenes to each other, It is also very effective for bonding polar materials such as wood. 2) It can be formed into a film by an extruder. 3) It can be extrusion-laminated with a polypropylene film. 4) Damage to the polypropylene film. Low-temperature bonding that does not give is possible. 5) It is colorless and transparent.

The hot melt adhesive for polypropylene resin of the present invention comprises an α-olefin copolymer and a tackifier as main components. The α-olefin copolymer is a copolymer composed of two or more monomers of α-olefins, and may be a copolymer containing a small amount of other copolymerizable monomers as necessary. it can. α-olefins include ethylene, propylene, pentene-1, 4-methylpentene
1, butene-1, hexene-1, octene-1, decene
1, dodecene-1. Of these, propylene, ethylene, pentene-1, 4-methylpentene-1,
Decene-1 and hexene-1 are preferred. Particularly preferred is a copolymer composed of propylene, ethylene and butene-1, particularly a copolymer of ethylene and another α-olefin, that is, an ethylene / α-olefin copolymer.

The monomers copolymerizable with the α-olefin which can be used together with the α-olefins include vinyl esters of saturated carboxylic acids, unsaturated carboxylic acids, and alkyl esters of unsaturated carboxylic acids.

The important properties of an α-olefin copolymer are density and softening point. The density is 0.905 g / c
m ³ or less, preferably 0.990 g / cm ³ or less.
The softening point is 100 ° C. or less, preferably 90 ° C. or less as a Vicat softening point.

The α-olefin copolymer of the present invention can be prepared by polymerization in an autoclave under high temperature and high pressure in the same manner as ordinary polymerization of polyolefin. However, as the α-olefin copolymer used in the present invention, a commercially available α-olefin copolymer can be used. Commercially available α-olefin copolymers that can be used include “Taphma” (manufactured by Mitsui Petrochemical Co., Ltd.), “Bureon” (manufactured by Mitsui Petrochemical Co., Ltd.), “Shell Polybutylene” (Shell Chemical), "Nack Flex" (manufactured by Nippon Unicar),
"Excellen VL" (manufactured by Sumitomo Chemical Co., Ltd.) and the like.
These α-olefin copolymers may be used as a mixture of two or more. The α-olefin copolymer of the present invention also includes a resin modified with maleic anhydride or the like in order to improve the adhesiveness with a polar material.

The tackifier used in the present invention is preferably a saturated petroleum resin such as an aliphatic hydrocarbon, a cycloaliphatic hydrocarbon, or a hydrogenated petroleum resin. These are commercially available as products, for example, "Alcon" (Arakawa Chemical Industries, Ltd.),
"Escolets" (manufactured by Tonex), "FTR-6"
00 "(manufactured by Mitsui Petrochemical Industries, Ltd.)," Quinton "(manufactured by Zeon Corporation)," Rigalite "(manufactured by Rika Hercules) and the like can be used. As the tackifier, in addition to the saturated petroleum resin, an aromatic petroleum resin, rosin and a derivative thereof, a terpene resin, and the like can be added as necessary.

In the composition of the hot melt adhesive, the α-olefin copolymer and the tackifier are contained in an amount of 70 to 95% by weight and 5 to 5% by weight.
-30% by weight, preferably 75-90% by weight and 10-2
5% by weight, more preferably 80-90% by weight and 10-2
It is blended at a ratio of 0% by weight. If the amount of the α-olefin copolymer is less than 70% by weight, the proportion of the tackifier increases by that much, the tackiness becomes strong, and the handling becomes difficult, and the strength after bonding also becomes low. When the proportion of the α-olefin copolymer is more than 95% by weight, the adhesiveness to a polar material tends to decrease.

The hot melt composition may further contain an olefinic thermoplastic resin, an antioxidant, an ultraviolet absorber, a light stabilizer, a colorant, a filler, a coupling agent, etc. in order to adjust adhesive properties and other properties. Can also be blended. As the olefin-based thermoplastic resin, polyethylene resin, ethylene-vinyl acetate resin, ethylene-ethyl acrylate copolymer resin, ethylene-methyl acrylate copolymer resin, ethylene-acrylic acid copolymer resin, ethylene-methacrylic acid copolymer resin, Low-molecular-weight polyethylene, low-molecular-weight polypropylene and their acid-modified products are exemplified.

The hot melt adhesive of the present invention is obtained by mixing an α-olefin copolymer as a main component, a tackifier, and other additives as necessary, and then melt-kneading to obtain a uniform composition. be able to. Melt kneading can be carried out using a usual melt kneading machine for plastics. For example, a single-screw or twin-screw kneading extruder, a kneader, a heated-type melt-stirring tank, or the like can be used.

The melting point of the hot melt adhesive of the present invention is 12
The temperature is 0 ° C or lower, preferably 115 ° C or lower. Melting point is 12
If the temperature is higher than 0 ° C., a high temperature is required at the time of bonding, and partial melting or shrinkage of the polypropylene film occurs, which is not preferable. Further, the hot melt adhesive of the present invention has a fluidity represented by MFR of 1 to 50. The MFR value is preferably 2-4.
0, more preferably 3 to 30.

The present invention also includes a film-shaped hot melt adhesive obtained by forming the above-mentioned hot melt adhesive for polypropylene resin into a film shape. A conventional hot melt adhesive could not be obtained as a film because of its low melt viscosity, but the hot melt adhesive of the present invention can be formed into a film. The film-like hot melt adhesive thus obtained has no blocking property unlike a conventional hot melt adhesive, and can be wound up as a long product, or can be stacked and handled or stored. Such a film-like hot melt adhesive can be formed by casting the hot melt adhesive of the present invention using a T-die or by inflation molding.

The present invention also includes a heat-bondable polypropylene laminated film in which the hot melt adhesive of the present invention is laminated and adhered to one side of a polypropylene film. Such a laminated film can be manufactured in the same manner as in forming a normal plastic laminated film.

In the above description, the Vicat softening point is a softening temperature measured according to ASTM-D 1525, and is 50 ° C. with a 1 kg load applied to the needle.
The temperature at the time when the needle penetrated 1 mm by raising the temperature at a temperature rising rate of / 60 minutes is shown. MTM is ASTM-D123
8 is an index of liquidity measured according to
The weight of resin extruded in 10 minutes under a pressure of 2.16 kg / cm ² at ² ° C. is expressed in grams.

[0021]

The present invention will be described in more detail with reference to the following examples. Example 1 The following hot melt adhesive formulations were melt blended with an extruder pelletizer to make hot melt pellets. [Hot melt adhesive compounding composition] (1) Ethylene-α-olefin copolymer 80 parts by weight “Tuffma-A-4090” manufactured by Mitsui Petrochemical Co., Ltd. Density 0.89, Vicat softening point 65 ° C (2) Saturation Petroleum resin 20 parts by weight "Alcon P-115" manufactured by Arakawa Chemical Industries, Ltd. (3) Lubricant 0.2 parts by weight "Amide S" manufactured by Nippon Kasei Co., Ltd. The obtained pellets are extruded with a T-die extruder to a thickness of 80.
A hot melt adhesive in the form of a film having a thickness of μm was formed. The resulting hot melt adhesive had a melting point of 70 ° C. and an MFR of 4.5.

Using the hot melt adhesive film thus obtained, four kinds of materials shown in Table 1 were heated at 120 ° C. ×
Bonding was performed by hot pressing under bonding conditions of 1.5 kgf / cm ² × 2 minutes. The adhesive strength of the adhesive was measured by the method described below. The results are shown in Table 1.

[Table 1]

[Measurement Method of Adhesive Strength] Measured by an Instron type tensile tester. Peeling method: 180 ° peeling Peeling speed: 100 mm / min

Example 2 [Composition of Hot Melt Adhesive] (1) 80 parts by weight of ethylene-α-olefin copolymer “Excellen VL-400” manufactured by Sumitomo Chemical Co., Ltd. Density 0.990, Vicat softening point 60 ° C. 2) Saturated petroleum resin 20 parts by weight "Tonex", "Escolets 5300" (3) Lubricant 0.2 part by weight, Nippon Kasei Co., Ltd., "Amide S" The above hot melt adhesive compound was prepared in the same manner as in Example 1. To form a film. Table 1 shows the results of the adhesion test. The obtained hot melt adhesive has a melting point of 113 ° C. and M
FR was 3.9.

Comparative Example 1 [Composition of Hot Melt Adhesive] (1) 65 parts by weight of ethylene-α-olefin copolymer “TAHMA-A-4090” manufactured by Mitsui Petrochemical Industries, Ltd. (2) 35 parts by weight of saturated petroleum resin Arakawa Chemical Industry Co., Ltd., "Alcon P-115" (3) Lubricant 0.2 parts by weight Nippon Kasei Co., Ltd., "Amide S" Pellets of hot melt adhesive were prepared in the same manner as in Example 1, but were sticky. As a result, it was difficult to form a film using an extruder.

Comparative Example 2 [Composition of Hot Melt Adhesive] (1) 97 parts by weight of ethylene-α-olefin copolymer “TAHMA-A-4085” manufactured by Mitsui Petrochemical Co., Ltd. Density 0.88, Vicat softening point 55 ° C. (2) Saturated petroleum resin 3 parts by weight “Arucon P-100” manufactured by Arakawa Chemical Industries, Ltd. A film was formed in the same manner as in Example 1. Table 1 shows the results of the adhesion test. Adhesion with polypropylene was good but did not adhere to polar materials.

Example 3 The pellets obtained in Example 1 were extruded into a film by means of a T-die extruder and simultaneously laminated on one side of a polypropylene film (thickness: 100 μm) to form a hot melt hot melt. An adhesive-laminated polypropylene film was obtained (thickness of hot melt adhesive: 80 μm).
m). The wood plywood (5) was placed so that the adhesive side of the laminated polypropylene film thus produced was in contact with the plywood.
Plies, 12 mm thick) and 1 in a vacuum press
Heat bonding at 30 ° C, 3 kgf / cm ² , 30 seconds,
A plywood panel for a polypropylene film-coated concrete formwork was prepared. The adhesive strength between the plywood and the polypropylene film was 5.6 kgf / cm ² . Exposure to sunlight for one month to evaluate weatherability revealed no abnormalities.

[0028]

As described above, the hot melt adhesive for polypropylene resin of the present invention has excellent performance in bonding between polypropylene and between polypropylene and other different materials. Moreover, it can be extruded into a film by itself and can be used as a film-like hot melt adhesive.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication location C09J 7/02 JJV C09J 7/02 JJV JKE JKE 123/08 JBY 123/08 JBY // (C09J 123 / 02 157: 02)

Claims (7)

[Claims] 1. A hot-melt adhesive for polypropylene resin containing 70 to 95% by weight of an α-olefin copolymer and 5 to 30% by weight of a tackifier. 2. The hot melt adhesive for polypropylene resin according to claim 1, which has a film shape. 3. The hot melt adhesive for polypropylene resin according to claim 1, wherein the α-olefin copolymer is a copolymer containing ethylene as one of the constituent monomer components. 4. An α-olefin copolymer containing ethylene as one of the constituent monomer components has a density of 0.905 g / c.
m ³ or less, the hot melt adhesive polypropylene resin according to any one of claims 1, 2 or 3 Vicat softening point of 100 ° C. or less. 5. The hot melt adhesive for polypropylene resin according to claim 1, wherein the tackifier is a saturated petroleum resin. 6. A melting point of 120 ° C. or less and an MFR of 1 to 6.
The hot melt adhesive for polypropylene resin according to claim 1 or 2, wherein the adhesive is 50. 7. A heat-bondable polypropylene laminated film in which the hot melt adhesive according to claim 1 is laminated and adhered to one surface of a polypropylene film.