JP3053055B2 - Amorphous polyolefin resin granules and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amorphous polyolefin resin granule having improved surface tackiness and a method for producing the same. More specifically, the present invention provides a granulated body which does not block during storage of the granulated body by improving the surface tackiness of the amorphous polyolefin resin granulated body, and a method for producing the same.

[0002]

2. Description of the Related Art Amorphous polyolefin resins are used in a wide range of fields such as hot melt adhesives, floor materials, and flexible film materials because of their flexibility, low specific gravity, and environmental safety. . However, since the amorphous polyolefin contains a large amount of a relatively low molecular weight amorphous component,
In the form of pellets or crumbs, there are disadvantages such as high surface tackiness, easy blocking itself, and difficulty in taking out the raw materials. For this reason, attempts have been made to add various additives to amorphous polyolefin to prevent tackiness (JP-A-59-33339, JP-A-59-43044). However, these methods have insufficient effects, and there are problems such as migration of the added additives.

[0003]

SUMMARY OF THE INVENTION The present invention provides an amorphous polyolefin resin granule which improves the surface tackiness of the amorphous polyolefin resin granule and does not block the granule, and a method for producing the same. Things.

[0004]

The amorphous polyolefin of the present invention has a boiling n-heptane insoluble content of 10% by weight or less, is substantially amorphous, and has almost no crystallizable portion. Those that do not have a spherulite structure are targeted. Here, the measurement of the boiling n-heptane insolubles was carried out by using a Soxhlet extraction method and using about 2 g of a 3 to 5 mm square die-shaped sample. As the amorphous polyolefin used in the present invention, amorphous polypropylene,
Copolymers of amorphous propylene with other α-olefins and the like can be mentioned. For example, atactic polypropylene by-produced during the production of crystalline polypropylene may be used, or may be produced from raw materials and used. In the case of target production, for example, using a titanium-supported catalyst supported on magnesium chloride and triethylaluminum in the presence of hydrogen /
Alternatively, it can be obtained by polymerizing a raw material monomer in the absence of hydrogen. From the viewpoint of the stability of raw material supply and the stability of quality, it is preferable to use a predetermined amorphous polyolefin produced for the purpose. In addition, if there is a corresponding suitable commercial product, a commercial product can be appropriately selected and used.

Specific examples of the amorphous polyolefin of the present invention include polypropylene, propylene / ethylene copolymer, propylene / butene-1 copolymer, and propylene / propylene copolymer.
Butene-1 / ethylene-3 terpolymer, propylene / hexene-1 / octene-1 / 3 terpolymer, propylene / hexene-1 / 4-methylpentene-1 / 3 terpolymer, polybutene-1 And the like. The amorphous polyolefin which is the object of the present invention is preferably applied to those having a low molecular weight component content and a number average molecular weight of 20,000 or less.

The amorphous polyolefin resin is usually extruded into a water bath in a molten state and simultaneously cut in water by a rotary cutter or the like and cooled to form a spherical or columnar amorphous polyolefin resin granule. Being manufactured. In this case, since the temperature of the water in the water tank is usually set in a temperature range of 0 to 30 ° C., the amorphous polyolefin resin extruded into the water tank is rapidly cooled and solidified. In addition to the fact that the amorphous polyolefin resin is substantially amorphous and hardly has a portion to be crystallized, the amorphous polyolefin resin granules produced by the above-described method are solidified by quenching and solidifying. In the temperature rise measurement mode using a differential scanning calorimeter, no significant endothermic peak is shown in a region higher than the glass transition temperature of the amorphous polyolefin resin.

The measurement by the differential scanning calorimeter was performed as follows. The measurement was performed using a DSC-50 manufactured by Shimadzu Corporation as a differential scanning calorimeter with a sample amount of about 10 mg, a measurement atmosphere in a nitrogen atmosphere, and indium as a calorimetric standard. A sample cut out from the amorphous polyolefin resin granule in an amount of about 10 mg was set in a sample measuring section of a differential scanning calorimeter, and then cooled at a rate of 10 ° C./min to −42.
C. and left at -42.degree. C. for 5 minutes. After that, the temperature is increased from -40 ° C to 200 ° C at a rate of 20 ° C / min in the temperature rising measurement mode.
The measurement was made up to ° C. When an endothermic peak appeared in a region higher than the glass transition temperature of the sample, the endothermic amount was calculated using a straight line obtained by directly extrapolating the specific heat curve of the completely molten state of the sample to the lower temperature side as a baseline. Amorphous polyolefin resin granules that do not show a significant endothermic peak in the region higher than the glass transition temperature in the temperature measurement mode using a differential scanning calorimeter have strong surface tackiness, for example, packing the granules in a cardboard box. In this case, the granules were strongly blocked by each other, so that it was difficult to take them out of the cardboard box.

As a result of various studies to improve such an amorphous polyolefin resin granule having a large surface tackiness,
When the granulated material is measured in a temperature rise measurement mode by a differential scanning calorimeter, the amorphous polyolefin resin having an endothermic peak of 2 Joule / g or more in a region higher than the glass transition temperature of the amorphous polyolefin resin. The present inventors have found that granules can prevent surface stickiness of the granules and completed the present invention.

As a method for granulating an amorphous polyolefin resin having such an endothermic peak, the amorphous polyolefin resin in a molten state is gradually cooled and / or solidified, and / or the amorphous polyolefin resin is heated at a temperature higher than the glass transition temperature. A method of heat-treating the polyolefin resin may be used. As a method for slowly cooling and solidifying an amorphous polyolefin resin in a molten state, for example, when it is melted by an extruder, the molten extrudate is cooled and solidified in the air as it is, or cut in water at 40 ° C. or higher. Or a method of cutting a strand cooled and solidified in a water temperature of 40 ° C. or more. At this time, if the water temperature at the time of hot cutting and the water temperature at the time of strand cutting are lower than 40 ° C., a sufficient slow cooling effect cannot be obtained, and the produced granules have a temperature lower than the glass transition temperature when measured by a differential scanning calorimeter. Does not show a significant endothermic peak in the high temperature range, and the surface tackiness of the granules is not improved. The effect of improving the surface tackiness is more effective as the cooling water temperature is higher. However, if the temperature is close to the softening point of the amorphous polyolefin resin, solidification is not sufficiently performed, which is not preferable.

Regarding the condition of the other method for producing the amorphous polyolefin resin granules having improved surface tackiness, that is, the method of heat treatment at a temperature higher than the glass transition temperature, the treatment temperature is the glass transition temperature. The effect of improving the surface tackiness is higher as the temperature is higher than the temperature. However, it is not preferable that the temperature is close to the softening point of the amorphous polyolefin resin because the resin becomes too soft and it is difficult to maintain the shape. The longer the treatment time is, the higher the effect of improving the surface tackiness is. However, if the heat treatment is carried out at a high temperature for a long time, thermal deterioration such as coloring occurs, which is not preferable. Usually, the heat treatment time is preferably about 10 minutes to 5 hours. In a temperature rise measurement mode using a differential scanning calorimeter, a method for producing a polyolefin resin granule having an endothermic peak of 2 Joule / g or more in a region higher than the glass transition temperature of an amorphous polyolefin resin is described below. The method of gradually cooling and solidifying the amorphous polyolefin resin and the method of heat-treating the amorphous polyolefin resin at a temperature higher than the glass transition temperature of the amorphous polyolefin resin may be performed alone or in combination.

[0011]

As described above, the amorphous polyolefin resin granules of the present invention have improved surface tackiness and hardly block the granules, so that they can be easily handled.

[0012]

【Example】

Example 1 As an amorphous polyolefin resin, a propylene / butene-1 copolymer (trade name: Ubetak UT2780, manufactured by Ube Lexen Co., Ltd., with a weight ratio of propylene / butene-1 of 65)
/ 35, boiling n-heptane insoluble content 5% by weight, number average molecular weight 6,500, glass transition temperature -24 ° C). After the amorphous polyolefin resin was melted at a temperature of about 130 ° C., it was extruded into a water tank whose temperature was controlled to 60 ° C. by the action of a pump. The amorphous polyolefin resin in the molten state was extruded into a water tank, and at the same time, was cut into a spherical shape by a rotary cutter to produce an amorphous polyolefin granule. The amorphous polyolefin granules were slowly cooled by being left in a water bath controlled at 60 ° C. for about 1 hour, and then taken out of the water bath. The obtained spherical amorphous polyolefin resin granules were spread in a room, air-dried, and then dried at room temperature under reduced pressure.
Approximately 10 mg of a sample was cut out from the spherical amorphous polyolefin resin granule dried under reduced pressure, and the measurement was carried out by a differential scanning calorimeter by the method described above. It has an endothermic peak in a temperature range of 60 to 90 ° C, and an endothermic amount of 6.4 Joule / g.
Met. The produced amorphous polyolefin resin granules have almost no surface tackiness, and even after packing about 5 kg of amorphous polyolefin resin granules in a cardboard box and leaving them to stand for one month, there is almost no blocking between the granules. I couldn't.

Example 2 As an amorphous polyolefin resin, a propylene / ethylene copolymer (trade name: Ubetack UT2585, manufactured by Ube Lexen Co., Ltd., weight ratio of propylene / ethylene: 85/1)
5, boiling n-heptane insolubles 0.7% by weight, number average molecular weight 7,100, glass transition temperature -34 ° C), and the temperature of the water tank was 90 ° C, except that the water tank temperature was 90 ° C. A crystalline polyolefin resin granule was produced. When the manufactured amorphous polyolefin resin granule was measured by a differential scanning calorimeter in the same manner as in Example 1, it was found to be 90 to 120.
It has an endothermic peak in the temperature range of
oule / g. The surface adhesion of the amorphous polyolefin resin granules was almost nonexistent, and even when packed in a cardboard box in the same manner as in Example 1, almost no blocking of the granules was observed.

Comparative Example 1 Using the same amorphous polyolefin resin as in Example 1,
An amorphous polyolefin resin granule was produced in the same manner as in Example 1 except that the temperature of the water tank was changed to 10 ° C. When the produced amorphous polyolefin resin granule was measured by a differential scanning calorimeter in the same manner as in Example 1, no significant endothermic peak was observed in a region higher than the glass transition temperature of -24 ° C. The amorphous polyolefin resin granules had severe surface tackiness, and the packing of the granules was intense when packed in a cardboard box in the same manner as in Example 1.

Comparative Example 2 Using the same amorphous polyolefin resin as in Example 2,
An amorphous polyolefin resin granule was produced in the same manner as in Example 1 except that the temperature of the water tank was changed to 10 ° C. When the produced amorphous polyolefin resin granule was measured by a differential scanning calorimeter in the same manner as in Example 1, no significant endothermic peak was observed in a region higher than the glass transition temperature -34 ° C. The amorphous polyolefin resin granules had severe surface tackiness, and the packing of the granules was intense when packed in a cardboard box in the same manner as in Example 1.

Continuation of the front page (56) References JP-A-1-308411 (JP, A) JP-A-5-310951 (JP, A) JP-A-7-258422 (JP, A) JP-A-3-500182 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08F 6/10 C08J 3/12

Claims (2)

(57) [Claims] 1. An amorphous polyolefin resin having a boiling n-heptane insoluble content of 10% by weight or less, and a glass transition temperature of an amorphous polyolefin resin granule in a temperature measurement mode by a differential scanning calorimeter. At higher temperatures than
An amorphous polyolefin resin granule having an endothermic peak of 2 Joule / g or more. 2. An amorphous polyolefin resin in a molten state.
Hot cut in 40 ° C or higher water
Or a strand cooled and solidified in a water temperature of 40 ° C or higher.
The method for producing an amorphous polyolefin resin granule according to claim 1, wherein the granulated material is cut .