JPH04236288A - Hot melt adhesive composition - Google Patents

Abstract

PURPOSE:To provide a hot melt adhesive composition having a low melt viscosity, a high ring and ball test-softening point, a high adhesive strength suitable for employment under high temperatures, and especially suitable for paper, wood, plastics, metals, etc. CONSTITUTION:A hot melt adhesive composition is characterized by comprising 100 pts.wt. of an amorphous polyolefin having a specific mol.wt. and 1-20 pts.wt. of crystalline polypropylene.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to hot melt adhesive compositions. More specifically, despite its low viscosity,
This invention relates to a hot melt adhesive composition for paper, wood, plastic, stone, plaster, cement, and metal, which has a high ring and ball softening point, is suitable for use in high-temperature environments, and has a large cohesive force.

0002

2. Description of the Related Art Recently, there has been a demand for hot melt adhesives that can bond extremely fine metals, plastic parts, thin films, nonwoven fabrics, and the like. This type of hot melt adhesive discharges the adhesive from a very thin applicator nozzle, so it requires a material with a lower viscosity, but it also requires high peel strength after adhesion and an upper limit temperature in the usable temperature range. required to be higher. Amorphous polyolefins with low viscosity, high temperature resistance, and high ring and ball softening points used in conventional hot melt adhesives have the drawback of low tensile elongation and insufficient cohesive strength as an adhesive. Therefore, for amorphous polyolefin with high cohesive force and low softening point,
By blending crystalline polypropylene for films and injection molded products, it is possible to raise the ring and ball softening point and increase the tensile elongation.

0003

[Problems to be Solved by the Invention] However, the adhesive obtained by blending crystalline polypropylene with the above-mentioned amorphous polyolefin does not meet the requirements for hot melt adhesives.
It has the disadvantage that it cannot achieve a low viscosity of 1,000 to 10,000 cps at 90°C and is difficult to coat. As a result of intensive research, the inventors aimed to obtain a hot melt adhesive with a good balance of physical properties such as low viscosity, high ring and ball softening point, excellent cohesive force, and tensile elongation. The present invention has now been completed.

0004

[Means for Solving the Problems] According to the present invention, (a)
100 parts by weight of an amorphous polyolefin with a number average molecular weight of 1,000 to 20,000 and a propylene component of 50% by weight or more, and (b) a number average molecular weight of 1,000 to 25,000
There is provided a hot melt adhesive composition comprising 1 to 20 parts by weight of crystalline polypropylene.

The present invention will be explained in more detail below. For the amorphous polyolefin containing 50% by weight or more of a propylene component, which is component (a) of the present invention, atactic polypropylene produced as a by-product during the production of crystalline polypropylene may be used, or a predetermined propylene component may be obtained from raw materials. Polypropylene and copolymers of propylene and other α-olefins can be produced and used. In the case of desired production, for example, a titanium-supported catalyst supported on magnesium chloride and triethylaluminum may be polymerized in the presence of hydrogen. From the viewpoint of supply stability and quality stability, it is preferable to use a specified amorphous polyolefin produced for the purpose. Furthermore, the amorphous polyolefin has a number average molecular weight of 1
,000-20,000, preferably 1,500-15
,000.

Specifically, polypropylene, propylene/ethylene copolymer, propylene/butene-1 copolymer, ternary copolymer of propylene, butene-1 and ethylene, having a propylene content and molecular weight within the above ranges; Examples include amorphous polyolefins whose main component is propylene, such as copolymers of propylene and hexene-1, octene-1 or 2-methylpentene-1. Among these, the propylene/ethylene copolymer has an ethylene content of 0 to 30% by weight, preferably 1 to 20% by weight.
It is. When the ethylene content is greater than 30% by weight, the adhesive becomes too soft and has too much surface tackiness, making it difficult to use as an adhesive. In addition, for propylene-butene-1 copolymer, the butene content is 0 to 5.
0% by weight, preferably 5-45% by weight. If the butene-1 content is greater than 50% by weight, the softening point will be too low.

Furthermore, the amorphous polyolefin of the present invention is
It is preferable that the content insoluble in boiling n-heptane, that is, the content insoluble in Soxhlet extraction with boiling n-heptane is 40% by weight or less, preferably 20% by weight or less, and more preferably 15% by weight or less. Furthermore, it is preferable that the amorphous polyolefin of the present invention hardly generates an endothermic peak during crystal melting in temperature rise measurement using a differential scanning calorimeter. In the amorphous polyolefin of the present invention, if the content insoluble in boiling n-heptane is higher than the above range or if the heat of crystal fusion is large, when used as an adhesive, the open time may be too short, or the flesh may become thin after application. This is not preferable because it causes problems such as changes in adhesive strength over time. As the amorphous polyolefin in the present invention, for example, commercially available REXT
AC) etc. can be used.

The number average molecular weight of the crystalline polypropylene as the component (b) in the present invention is 1,000 to 25,000.
, preferably 2,000 to 20,000. When the number average molecular weight exceeds 25,000, the viscosity of the hot melt adhesive becomes high, making it difficult to apply with a hot melt applicator.Moreover, while the viscosity increases significantly, the ring and ball softening temperature increases. Because of this, even if a hot melt adhesive that can withstand high temperatures is prepared, the viscosity is too high to be suitable for practical use. Further, if the number average molecular weight is less than 1,000, the molecular weight is too low, resulting in low adhesive strength and a decrease in adhesive strength due to blooming, which is not preferable.

[0009] The polypropylene having the above number average molecular weight is
A low molecular weight polypropylene polymer having a number average molecular weight within the above range may be used, or a high molecular weight polypropylene may be treated with peroxide or the like to lower its molecular weight. Further, crystalline polypropylene copolymers such as block copolymers and random copolymers can also be used. Among these crystalline polypropylenes, random copolymers and polypropylene homopolymers having an ethylene content of less than 3% by weight are particularly preferred.

In the present invention, the blending ratio of the amorphous polyolefin as the component (a) and the crystalline polypropylene as the component (b) is as follows: 100 parts by weight of the component (a) and 1 part by weight of the component (b).
~20 parts by weight, preferably 2 to 18 parts by weight. If the amount of the crystalline polypropylene (b) component is less than this, the effect of addition will be small, and if it is more than 20 parts by weight, the flexibility and long open time, which are characteristics of amorphous polyolefin, will be impaired.

The composition of the present invention containing only the amorphous polyolefin as the component (a) and the crystalline polypropylene as the component (b) can be used alone as an adhesive. In addition, if higher adhesion is required depending on the adherend, it is possible to increase adhesion by adding tackifiers or resins, change compatibility, or adjust cohesive force. can. In the present invention, the blending ratio of the tackifier and the like is preferably 0 to 70 parts by weight based on 100 parts by weight of the blend of components (a) and (b). When the amount exceeds 70 parts by weight, the effect of blending the amorphous polyolefin and crystalline polypropylene of the present invention is lost.

[0012] The tackifier used in the present invention is as follows:
Natural rosin (gum rosin, wood rosin, tall oil rosin, etc.), modified rosin (polymerized rosin, hydrogenated rosin, etc.), coumaron/indene resin, terpene resin, aliphatic/alicyclic/aromatic petroleum resin, phenolic resin Resin etc. can be used. In addition, the resins include ethylene/vinyl acetate copolymer, ethylene/acrylic acid copolymer, ethylene/ethyl acrylate copolymer, ethylene/methyl acrylate copolymer, styrene/ethylene/butylene copolymer,
Styrene block copolymers, ethylene-propylene copolymers or ethylene-butene copolymers with a molecular weight of 30,000 or more, polybutenes, waxes, and the above polymers and copolymers modified with acids, metal salts of acids, halogens, etc. Union,
Liquid oil etc. can be used. The above-mentioned tackifiers and resins can be used alone or in combination of two or more.

Furthermore, conventionally known additives such as various fillers, antioxidants, etc. may be added as compounds other than those mentioned above. As the filler, clay, talc, calcium carbonate, barium carbonate, etc. can be used, and organic and inorganic fibrous reinforcing materials can also be used. Antioxidants include dilaurylthiodipropionate, pentaerythrityl-tetrakis [
3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-
di-t-butyl-4-hydroxyphenyl) propionate, tris(2,4-di-t-butylphenyl) phosphite, 2,6-di-tert-butyl-4-methylphenol, phenyl-α-naphthylamine, etc. can be used.

In the present invention, in order to blend crystalline polypropylene, other polymers such as additives, and fillers into the amorphous polypolefin, these components may be mixed and heated in a container, and stirred. Rolls, Banbury mixers, kneaders, extruders, etc. used for mixing can also be used. Since the adhesive composition of the present invention melts when heated, it can be molded into various shapes such as blocks, pellets, strings, and films. The adhesive composition of the present invention can be applied by using a conventional hot melt adhesive applicator to melt the adhesive onto the adherends and bonding the adherends together, or by applying the adhesive to one of the adherends in advance. After application, a method of stacking the other adherend and heating it, a method of laminating a film-like adhesive using a laminator, etc. can be used.

Adherents to which the adhesive composition of the present invention can be used include paper, cloth, wood, synthetic resins such as polyethylene, polypropylene, and polyvinyl chloride, as well as plaster, cement, stone, Examples include metallic glass. In addition, moisture-proof/waterproof paper with a sandwich-like structure made of paper and/or paperboard bonded together with hot-melt adhesive, and moisture-proof/waterproof paper with paper and/or paperboard coated with hot-melt adhesive on one side. Can be used. Furthermore, it can be used as an adherend to fill gaps between objects of the same type or different types as described above, that is, it can be used as a sealant.

[0016]

[Examples] The present invention will be explained in detail below with reference to Examples. However, the present invention is not limited to the following examples. In addition, in the following examples and comparative examples, each physical property etc. was measured by the following method. (1) Viscosity (cps) Measured at 190°C in accordance with JIS K7117. (2) Ring and ball softening point (°C) Based on JIS K2207. (3) Penetration (1/10mm) Based on JIS K2207. (4) Breaking strength (kg/cm2) and elongation (%) J
Based on IS K7113, using a No. 2 type test piece,
Measured at a tensile speed of 50 mm/min. (5) Adhesive strength (kg/25mm) After applying the obtained adhesive composition onto a polyethylene terephthalate film to a thickness of 60 μm, another polyethylene terephthalate film was overlaid at 120°C, 3 kg/cm.
The films were bonded together by pressing for 10 seconds at a pressure of 2. This bonded film was cut into strips with a width of 25 mm, and the T-peel strength was measured at each temperature shown in Table 1 at a peeling rate of 300 mm/min.

Example 1 As an amorphous polyolefin, a product name REXTAC RT manufactured by Rexen Corporation in the United States has a weight ratio of propylene/butene-1 of 65/35 and a number average molecular weight Mn of 3,600.
2715 propylene-butene-1 copolymer at 98% by weight, crystalline polypropylene manufactured by Ube Industries, Ltd. under the trade name ZT having a number average molecular weight Mn of 12,000.
-1259 homopolypropylene was added in an amount of 2% by weight and heated and melted to prepare a hot melt adhesive. Next, each physical property of the obtained adhesive was measured. The measurement results are shown in Table 1.

Example 2 A hot melt adhesive was obtained in the same manner as in Example 1, except that the blending amounts of amorphous polyolefin and crystalline polypropylene were changed to 96% by weight and 4% by weight. Each physical property of the obtained adhesive was measured. The measurement results are shown in Table 1.

Example 3 A hot melt adhesive was obtained in the same manner as in Example 1, except that the blending amounts of amorphous polyolefin and crystalline polypropylene were changed to 90% by weight and 10% by weight. Each physical property of the obtained adhesive was measured. Table 1 shows the measurement results.
It was shown to.

Example 4 In Example 2, a propylene/ethylene weight ratio of 97/3 manufactured by Lexen Corporation in the United States was used as the amorphous polyolefin.
The product name RE has a number average molecular weight Mn of 3,400.
A hot melt adhesive was obtained in the same manner as in Example 2 except that XTAC RT2215 was used. Each physical property 1 of the obtained adhesive was measured. The measurement results are shown in Table 1.

Example 5 In Example 1, a propylene/ethylene weight ratio of 85/1 manufactured by Lexen Corporation in the United States was used as the amorphous polyolefin.
5, and the number average molecular weight Mn is 4,700.
A hot melt adhesive was obtained in the same manner as in Example 1 except that EXTAC RT2535 was used. Each physical property of the obtained adhesive was measured. The measurement results are shown in Table 1.

Example 6 In Example 1, the amount of amorphous polyolefin was increased to 9.
The hot melt adhesive was prepared in the same manner as in Example 1, except that 5% by weight of Viscoll 330P, a product name manufactured by Sanyo Chemical Industries, Ltd. and having a number average molecular weight Mn of 15,000, manufactured by Sanyo Chemical Industries, Ltd. was blended as the crystalline polypropylene. I got it. Each physical property of the obtained adhesive was measured. Table 1 shows the measurement results.
It was shown to.

Example 7 A hot melt adhesive was obtained in the same manner as in Example 1, except that the amounts of amorphous polyolefin and crystalline polypropylene were changed to 90% by weight and 10% by weight. Each physical property of the obtained adhesive was measured. Table 1 shows the measurement results.
It was shown to.

[0024]

[Table 1]

Comparative Example 1 Propylene-butene-1 copolymer manufactured by Rexen, Inc., USA, used as an amorphous polyolefin in Example 1 without adding crystalline polypropylene, product name REXT.
A hot melt adhesive made only of AC RT2715 was created. Each physical property of the obtained adhesive was measured. The measurement results are shown in Table 2.

Comparative Example 2 A propylene-ethylene copolymer manufactured by Rexen Co., Ltd. (trade name: REXTA) was used as an amorphous polyolefin in Example 4 without adding crystalline polypropylene.
A hot melt adhesive made only of C RT2215 was created. Each physical property of the obtained adhesive was measured. The measurement results are shown in Table 2.

Comparative Example 3 A propylene-ethylene copolymer manufactured by Rexen, Inc., USA, which was used as an amorphous polyolefin in Example 5 without adding crystalline polypropylene (trade name: REXTA)
A hot melt adhesive made only of C RT2535 was created. Each physical property of the obtained adhesive was measured. The measurement results are shown in Table 2.

Comparative Example 4 90% by weight of the propylene-butene-1 copolymer, trade name REXTAC RT2715, manufactured by Rexen, USA, used in Example 1 as the amorphous polyolefin, and 90% by weight of the propylene-butene-1 copolymer manufactured by Ube Industries, Ltd. as the crystalline polypropylene. A hot melt adhesive was prepared in the same manner as in Example 3, except that 10% by weight of a block polypropylene copolymer with the trade name J950HK having a number average molecular weight Mn of 30,000 was used. Each physical property of the obtained adhesive was measured. Table 2 shows the measurement results.
It was shown to.

Comparative Example 5 In Comparative Example 4, a hot melt adhesive was prepared using a random polypropylene copolymer with a number average molecular weight Mn of 52,000, sold by Union Polymer Co., Ltd. under the trade name FM801, as the crystalline polypropylene. did. Each physical property of the obtained adhesive was measured. The measurement results are shown in Table 2.

[0030]

[Table 2]

As is clear from the above Examples and Comparative Examples, the adhesive comprising components (a) and (b) of the present invention has a good balance between viscosity and ring and ball softening point increase, and is stable even at high temperatures. It can be seen that low viscosity is maintained. On the other hand, in the comparative example, the softening point of component (a) alone was low, and when a crystalline polypropylene other than component (b) of the present invention was used, the viscosity increased significantly compared to the increase in the softening point for practical use. It turns out that there is no gender.

Examples 8 to 14 In each of Examples 1 to 7, an alicyclic compound manufactured by Mitsui Petrochemical Industries, Ltd. was added as a tackifier to the respective blends of amorphous polyolefin and crystalline polypropylene. 43% by weight of petroleum resin trade name Hiretz T1115
was added to create a hot melt adhesive. Each physical property of the obtained adhesive was measured. The measurement results are shown in Table 3.

Comparative Examples 6 to 10 In each of Comparative Examples 1 to 5, amorphous polyolefin or a blend of amorphous polyolefin and crystalline polypropylene was added to Mitsui Petrochemical Industries Ltd. as a tackifier. A hot melt adhesive was prepared by adding 43% by weight of Hiretz T1115, an alicyclic petroleum resin manufactured by the company. Each physical property of the obtained adhesive was measured. The measurement results are shown in Table 4.

[0034]

[Table 3]

[0035]

[Table 4]

From the above Examples and Comparative Examples, it can be seen that the adhesive of the present invention has high adhesive strength at high temperatures and is excellent in high temperature properties.

[0037]

Effects of the Invention The adhesive composition of the present invention, which is composed of amorphous polyolefin and crystalline polypropylene, has a low viscosity and good workability, but has a high softening point, no fluidity at high temperatures, and low cohesive strength. big. Therefore, it can be used as an adhesive for paper, wood, plastic, stone, plaster, cement, metal, etc.
In particular, it is suitable as a hot melt adhesive with high workability and a high usable temperature.

Claims (3)

[Claims] Claim 1: (a) Number average molecular weight 1,000-20
,000, 100 parts by weight of an amorphous polyolefin having a propylene component of 50% by weight or more, and (b) crystalline polypropylene 1 to 1 having a number average molecular weight of 1,000 to 25,000.
A hot melt adhesive composition comprising 20 parts by weight. 2. The hot melt adhesive composition according to claim 1, wherein the amorphous polyolefin is a propylene/ethylene copolymer containing 70 to 100% by weight of propylene and 0 to 30% by weight of ethylene. 3. The amorphous polyolefin contains 50 to 90% by weight of propylene and 10 to 50% by weight of butene-1.
The hot melt adhesive composition according to claim 1, which is a propylene-butene-1 copolymer.