KR930008156B1 - Hat melt adhesive compositions - Google Patents

Abstract

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Description

Hot Melt Adhesive Composition

The present invention relates to a hot melt adhesive composition useful for melt bonding paper, wood, plastic, stone, gypsum, cement and metal materials.

More specifically, the present invention is a specially synthesized product which is a specific synthetic product as a main component, but isotactic propylene, and is an amorphous (non-crystalline) propylene-ethylene random having high bonding properties, low softening point, high permeability and high freeze resistance It relates to a copolymer.

It is well known that atactic polypropylene is useful as a main component of conventional low boiling point hot melt adhesives. This atactic polypropylene is available as a by-product by the process for producing crystalline isotactic polypropylene resins and is an inexpensive amorphous polymer having a relatively low molecular weight and low viscosity.

Commercially available crystalline isotactic polypropylene resins include propylene homopolymers, propylene-ethylene random copolymers and propylene-ethylene block copolymers thereof. In the copolymers, the content of copolymerized ethylene is usually 5 weights or less. Thus, the atactic propylene copolymer produced as a byproduct of the isotactic propylene-ethylene copolymer contains copolymerized ethylene in an amount of about 5 to about 6 weight percent or less. This type of atactic propylene copolymer exhibits unsatisfactory properties at low temperatures due to the low content of ethylene.

The amorphous polypropylene produced as a byproduct in the preparation of the propylene-ethylene block copolymer contains a rubber fraction that can be extracted from the block copolymer. This rubber fraction consists of a propylene-ethylene copolymer containing a relatively large amount of copolymerized ethylene, but this propylene-ethylene copolymer is not a random copolymer and has a stickiness, and its composition is unstable so that its quality and properties, For example, its softening point and hardness are not uniform.

In addition, the molecular weight of the atactic polypropylene depends on the desired molecular weight of the isotactic polypropylene, and therefore the melt viscosity of the atactic polypropylene is not uniform. Occasionally, atactic polypropylene contains a catalyst residue, and when the atactic polypropylene is separated from the isotactic polypropylene using an extraction solvent, the separated atactic polypropylene contains a solvent residue.

When atactic polypropylene having the above disadvantages is used as a main component, the resulting hot melt adhesive exhibits poor bonding properties at low temperatures, and atactic polypropylene because of its odor, high flammability and low softening point, and uniformity of its melt viscosity. It is disadvantageous in that it is difficult to control the adhesive properties of the adhesive to a predetermined constant level.

Therefore, there is an urgent need to develop new types of hot melt adhesives that do not have the disadvantages of conventional atactic polypropylene-containing adhesives.

Unexamined Japanese Patent Publication No. 266175/89 discloses a hot melt adhesive composition containing an amorphous propylene-ethylene random copolymer containing 8 to 30% by weight of copolymerized ethylene as a main component and having a number average molecular weight of 1,000 to 20,000. Described. The adhesive composition exhibits enhanced properties at low temperatures, ie, satisfactory bonding properties at about 0 ° C., but when used at high temperatures above 50 ° C., the adhesive composition softens and is unsuitable for bonding materials or sealing materials at high temperatures.

An object of the present invention is a hot melt adhesive composition which hardly softens and melts at a relatively high temperature of 50 ° C. or higher, exhibits satisfactory bonding properties at low temperatures of 0 ° C. or less, is odorless, not flammable, and has a suitable softening point and melting boiling point. To provide.

It is a further object of the present invention to provide a hot melt adhesive composition which contains a specially synthesized adhesive polymer as a main component and has predetermined uniform properties and constant quality.

The object is 30 to 100% by weight of an amorphous propylene-ethylene random copolymer having a molecular weight of 1,000 to 20,000 and containing copolymerized ethylene in an amount of at least 2% by weight and less than 8% by weight, based on the total weight of the copolymer. Achievable by a hot melt adhesive composition containing 0 to 70 weight percent and 0 to 70 weight percent of additional resin material except for the amorphous propylene-ethylene random copolymer.

The hot melt composition contains certain amorphous (amorphous) propylene-ethylene random copolymers, tackifiers and additional resinous materials.

Certain amorphous propylene-ethylene copolymers that may be used in the present invention are not by-products derived from the production of propylene-ethylene copolymers, but are prepared for specific purposes in polymerization products.

For example, certain amorphous propylene-ethylene random copolymers that can be used in the present invention having a number average molecular weight of 1,000 to 20,000 and a content of copolymerized ethylene of at least 2% by weight and less than 8% by weight are titanium retained on a magnesium chloride carrier. In the presence of a catalyst composition containing a compound and triethyl aluminum and a molecular weight modifier consisting of hydrogen, a mixture consisting of liquefied propylene and a predetermined amount of ethylene mixed with liquefied propylene can be copolymerized to prepare as a main product or as a desired product. .

Because certain propylene-ethylene random copolymers are copolymerization reaction products made for specific purposes, these copolymers have a much more uniform softening point and melting point than conventional atactic propylene-ethylene copolymers prepared as by-products of isotactic copolymers. Do. It is also easy to adjust the molecular weight, the copolymerization weight ratio of propylene to ethylene, the softening point and the melt viscosity of the random copolymer to the desired values.

In addition, the random copolymer can be produced without using a solvent, and since the random copolymer does not contain a solvent, there is no odor and it is not flammable.

When the number average molecular weight is less than 1000, the resultant amorphous propylene-ethylene random copolymer has a cohesive force so low that the binding properties are not satisfactory. When the number average molecular weight is 20,000 or more, the resulting amorphous random copolymer is too high in melt viscosity to be unsatisfactory in workability. In addition, this high melt viscosity copolymer is difficult to blend with another polymer having a very different melt viscosity, and even if blended, the resulting polymer blend is unsatisfactory in fluidity and cannot be uniformly coated.

If the content of copolymerized ethylene is less than 2% by weight, the resulting copolymer exhibits extremely poor low temperature properties and very low compatibility with the ethylene polymer or copolymer.

If the copolymerized ethylene content is 8% by weight or more, the resulting copolymer has a low softening point and undesirably high flexibility at high temperatures, thus poor cohesion and not suitable for high temperature.

The hot melt adhesive composition of the present invention may contain only an amorphous propylene-ethylene random copolymer as the main component of the adhesive, or may contain a mixture of 30 wt% or more of the copolymer and 70 wt% or less of the additional resin material of the tackifier 70 wt% or less. Can be. If the binding properties of the amorphous propylene-ethylene random copolymer are not suitable for the product to be bound, a tackifier and an additional resinous material are added to the amorphous copolymer to determine the bond strength, compatibility with the bound product, and cohesion, respectively. Adjust with

Amorphous propylene-ethylene random copolymers can be modified using acids such as maleic anhydride.

In the adhesive composition of the present invention, the content of the amorphous copolymer should be at least 30% by weight. If this content is less than 30% by weight, the resulting adhesive composition may not clearly exhibit the properties derived from the amorphous copolymer.

Tackifiers that can be used in the present invention are preferably natural rosin (e.g. rubber rosin, wood rosin, and tol oil rosin), modified rosin (e.g. polymerized rosin, hydrogenated rosin, and maleic acid rosin), couma At least one component selected from the group consisting of lon-indene resins, terpene resins, petroleum resins and phenol resins.

Further resin materials different from certain amorphous propylene-ethylene random copolymers are preferably ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-ethyl acrylate copolymers styrene-ethylene-butylene, styrene block copolymers. At least one constituent selected from the group consisting of ethylene-propylene copolymers having a number average molecular weight of at least 30,000, ethylene-butene copolymers, polybutenes, beeswax and acids, metal salts and polymer compounds of halogen-modified polymers, Is halogen.

The adhesive composition may contain an adhesive that can be used in conventional adhesive materials and is selected from, for example, fillers and antioxidants.

The filler preferably contains at least one component selected from clay, talc, calcium carbonate, barium carbonate and organic and inorganic fiber reinforcements.

Antioxidants are, for example, dilauryl-thio-dipropionate, 2,6-di-tert-butyl-4methylphenol and phenyl- It contains naphthylamine.

The adhesive composition of the present invention may be prepared by uniformly blending certain amorphous propylene-ethylene random copolymers with other and additional ingredients in a blender while heating and stirring. The blender may be a roll blender, Banbury mixer, kneader and extruder.

The adhesive composition of the present invention can be heated to fuse and thus can be molded into any form, such as blocks, pellets, yarns and films.

In the method of applying the hot melt adhesive composition of the present invention, the adhesive composition is heat-melted, the melt is applied to the product to be bonded, and then the adhesive composition, the melt-coated product is bonded to each other. In another application method, the adhesive composition in liquid or powder form is applied to one or more of the articles to be bonded, and the articles are overlapped with each other through the applied adhesive composition layer, and then heat is fused to each other.

In another application method, the adhesive composition is molded into a film or sheet form, the adhesive composition film or sheet is sandwiched between the products to be joined, and the adhesive composition film or sheet-embedded product is then heat-fused to each other.

The hot melt adhesive compositions of the invention can be used in various products, such as paper sheets, textiles, wood, synthetic plastic resin products, such as polypropylene, polyethylene and polyvinyl chloride products, and gypsum, cement, stone and metal products. Is useful for fusion-binding.

In addition, the heat-melt adhesive composition of the present invention is a moisture-proof and waterproof paper sheet, or at least one surface of the paper sheet or cardboard, wherein two or more paper sheets or cardboard are bonded to each other through a hot melt adhesive composition to form a sandwich structure It can be used to make another type of moisture proof and waterproof sheet coated with this hot melt adhesive composition layer.

The hot melt adhesive composition of the present invention can also be used as a sealing material for preventing gaps or cracks in products.

The invention is further illustrated by the following specific examples.

Example 1

In an autoclave equipped with a stirrer, liquefied propylene mixed with ethylene contains a titanium compound containing tritium aluminum and a triethyl aluminum in a molar ratio of 100: 1 by weight of titanium retained on a magnesium chloride carrier. Copolymerization is carried out at a temperature of 80 ° C. in the presence of a catalyst composition and a molecular weight modifier consisting of hydrogen.

The resulting amorphous propylene-ethylene random copolymer was determined by gas permeation chromatography (GPC) and found to have a number average molecular weight of 7200 and a copolymerized ethylene content of 3.5% by weight.

Amorphous propylene-ethylene random copolymer was melted in a mixer equipped with a stirrer at a temperature of 170 ° C, and 50% by weight of a tackifier and Shiva-Arakawa, sold under the trade name Alcon P-125. Gaigi Age is mixed with 0.1 wt% of an antioxidant sold under the trade name Irganox 1010 while stirring to prepare a hot melt adhesive composition.

The surface of the polyethylene terephthalate film was coated with an adhesive composition to a thickness of 60 μm, a biaxially stretched polypropylene film was placed on the adhesive composition layer, and the resulting precursor laminate was subjected to 120 ° C. for 10 seconds under a pressure of 30 kg / cm 2. Heat-compress at

A 25 mm wide specimen is taken from the resulting laminate sheet and subjected to a T-peel test at a peel rate of 300 mm / min.

In addition, the adhesive composition is subjected to a needle permeation test according to Japanese Industrial Standard (JIS) K2207.

In addition, the heat resistance temperature of the adhesive composition under shear slip is determined by the following method.

The two polyethylene terephthalate films are bonded to each other on a bonding area of 20 mm x 25 mm through the adhesive composition in the manner described above.

The upper end of one of the bound films is fixed and a 1 kg load is applied to the lower end of the other of the bound films to heat the bonded films under these conditions at a heating rate of at least 100 ° C. per hour. The temperature at which the adhesive composition softens and the loaded film slips to separate from the fixed film is measured.

The results of the test are listed in Table 1.

Example 2

The same procedure as in Example 1 was conducted except that the number average molecular weight of the amorphous propylene-ethylene random copolymer measured by GPC was 7100 and the copolymerized ethylene content was 7.0% by weight.

The test results are shown in Table 1.

Example 3

50 parts by weight of amorphous propylene-ethylene random copolymer, 40 parts by weight of tackifier under the trade name Alcon P-125, and a melt index of 15 g / 10 minutes by Ube Industries as V319. The same procedure as in Example 1, except that 10 parts by weight of an additional resin material consisting of an ethylene-vinyl acetate copolymer having a content of 19% by weight and 0.1 parts by weight of an antioxidant (Irganox 1010) were blended to prepare an adhesive composition. Do this.

The test results are shown in Table 1.

Example 4

The same procedure as in Example 3 was carried out except that Example 2 was used instead of the propylene-ethylene copolymer.

The test results are shown in Table 1.

Control Example 1

The same procedure as in Example 1 was performed except that the number average molecular weight of the amorphous propylene-ethylene random copolymer measured by GPC was 7400 and the content of copolymerized ethylene was 14.2 wt%.

The test results are shown in Table 1.

Control Example 2

The same procedure as in Example 3 was carried out except that the one from Control Example 1 was used instead of the propylene-ethylene copolymer.

The test results are shown in Table 1.

TABLE 1

Note: (*) ₁ : Alcon P-125

(*) ₂ : ethylene-vinylacetate (19%) copolymer

(*) ₃ : Irganox 1010

Table 1 shows that the hot melt adhesive compositions of the present invention containing certain amorphous propylene ethylene random copolymers exhibit satisfactory bond strengths not only at low temperatures but also at high temperatures (eg 50 ° C.) and have stable properties and high workability. Able to know.

Claims (4)

30 to 100% by weight of an amorphous propylene-ethylene random copolymer having a number average molecular weight of 1000 to 20,000 and containing copolymerized ethylene in an amount of at least 2% by weight and less than 8% by weight based on the total weight of the polymer, tackifier 0 To 70 weight percent, 0 to 70 weight percent of additional resin material excluding the amorphous propylene-ethylene random copolymer. 2. The propylene-ethylene random copolymer of claim 1, wherein the amorphous propylene-ethylene random copolymer is based on the total weight of the mixture of liquefied propylene and mixture in the presence of a molecular weight modifier consisting of a catalyst composition containing titanium compound and triethyl aluminum held on a magnesium chloride carrier and hydrogen And a copolymerization product of a mixture with ethylene which occupies an amount of at least 2% by weight and less than 8% by weight. The adhesive composition according to claim 1, wherein the tackifier contains at least one component selected from the group consisting of natural rosin, modified rosin, coumarone-indene resin, terpene resin, petroleum resin and phenolic resin. The method of claim 1 wherein the additional resinous material is ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-ethylacrylate copolymer, ethylene-methyl acrylate copolymer, styrene-ethylene-butylene-styrene block air At least one component selected from the group consisting of copolymers, ethylene-propylene copolymers having a number average molecular weight of at least 30000, ethylene-butene copolymers, polybutenes, beeswax and polymer compounds of the above polymers modified with acids, metal salts and halogens Adhesive composition.