JPS5835224B2 - Asphalt materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an asphalt composition for injection molding.

For more details, see Asphalt with a penetration of 40 or less, 75~
25 wt%, aromatic petroleum resin with ring and ball method softening point of 100°C or higher, 50 to 50 parts to 100 parts of asphalt-aromatic petroleum resin.
The present invention relates to an asphalt composition for injection molding which is characterized by having excellent heat resistance and being hard, which is obtained by mixing 600 parts of the above.

Until now, expensive polymeric thermoplastic resins such as cellulose acetate, polystyrene, polyethylene, polypropylene, and polyvinyl chloride have been mainly used as materials for injection molding.
We have provided molded products in various shapes, but when disposing of these plastics when they are no longer needed, they emit excessive combustion calories due to their high molecular weight, or they emit corrosive and harmful gases due to decomposition during combustion. Because of this, the lifespan of incinerators has been shortened, and now they are being treated in the same way as non-combustible waste.

In addition, coal tar pitch is thermoplastic and inexpensive, and may be used as an injection molding material, but coal tar pitch tends to cause skin damage when it comes into contact with the human body, and is a carcinogen. Because it contains toxic substances such as highly suspected 3.4 benzpyrene, toxic gas and dust are generated when coal tar pitch and various compounding agents are heated and mixed, crushed into granules or powder, and heated and injection molded. This is not only harmful to those directly involved in the molding process, but also poses concerns about environmental pollution.

The present invention, based on the results of extensive research into injection molding compositions, has developed an excellent injection molding asphalt composition that is free from the above-mentioned drawbacks, is inexpensive, and can be used in conventional injection molding machines as is. This is what we provide.

That is, it has been found that an excellent asphalt composition for injection molding can be obtained which is harmless, inexpensive, has excellent heat resistance, and is hard.

The asphalt used in the present invention refers to straight asphalt obtained from vacuum distilled afterflame oil during petroleum refining, blown asphalt that is blown using air or a catalyst, and non-polar solvents such as liquefied propane or liquefied butane. Any propane or butane deasphalt asphalt toner obtained by extracting the oil fraction and precipitating it may be used, but the penetration is 40 or less, preferably 20 or less.

Here, the penetration is JIS K2530 (25℃, 100f
, 5 seconds).

For the purpose of the present invention (
If this mixture is used, the injection molded product will be soft and will be permanently deformed during storage, use, etc.

The aromatic petroleum resin referred to in the present invention refers to a C9 unsaturated aromatic resin having a boiling point of preferably 140° C. to 280° C., which is a cracked oil fraction obtained by thermal decomposition of petroleum and is liquid at room temperature. Aromatic petroleum resins obtained by thermal polymerization or polymerization of the main component fraction using a conventional Friedel-Krach type catalyst, or those obtained by adding an unsaturated dibasic acid anhydride such as maleic anhydride to these resins, JIS K253
Ring and ball softening point according to No. 1: 100°C or higher, preferably 120°C
It is a resin with a high softening point of ℃ or higher.

If a petroleum resin with a softening point lower than 100°C is blended for the purpose of the present invention, the softening temperature of the composition will be low (this
Not only does the cooling process during molding take longer, reducing productivity, but the heat resistance of molded products also becomes a problem, causing them to deform when left in hot places outdoors or when transported or stored in stacks.

In addition, the inorganic powder photosensitive agent as used in the present invention usually has a diameter of 0.
01μ~0.5mm inorganic powder, such as calcium carbonate, calcium sulfate, calcium suboxide, aluminum silicate, calcium fluoride, dolomite, diatomaceous earth, talc, clay, alumina white, mica powder,
aluminum sulfate, aluminum sulfate, barium sulfate,
These include lithopone, pumice powder, graphite powder, glass powder, zinc white, magnesium carbonate, carbon black, metal powder, or a mixture thereof.

Furthermore, small amounts of asbestos fibers, glass fibers, etc. can be added as necessary.

The quantitative relationship between the asphalt component and the aromatic petroleum resin component is 75 to 25 wt%, preferably 65 to 30 wt% of asphalt having a penetration of 40 or less.

When the amount of asphalt is more than 75 wt%, the asphalt is semi-molten even at relatively low temperatures, so a long cooling time is required during molding, which reduces productivity and makes the molded product weaker and softer. In addition, it is easy to permanently deform even under low loads, and when stored in the summer or left unattended, the surface of the molded product becomes sticky, causing individual molded products to adhere and become integrated, or deform and retain their original shape. do.

If the amount of asphalt is less than 25 wt% and the amount of aromatic petroleum resin is large, the composition will become extremely hard and brittle.
It can be destroyed by the slight impact during the mold release process during molding or during transportation.

In addition, this composition has poor fluidity when heated and molten during mixing and molding, and may also generate white smoke and bad odors.

The amount of inorganic brightening agent mixed with 100 parts of these asphalt-aromatic petroleum resins is 50 to 600 parts, preferably 100 to 500 parts.

If the amount of filler is more than 600 parts, the fluidity of the asphalt composition for injection molding will be reduced and the molding cycle will be extremely long, while if it is less than 50 parts, there will be problems with the dimensional stability and strength of the molded product. .

Furthermore, small amounts of antioxidants, processing aids, mold release agents, etc. can be added to the asphalt composition for injection molding of the present invention, if necessary.

The formulation and preparation of these asphalt-based compositions for injection molding are as follows:
Although the composition of the present invention can be easily prepared using machines used for mixing and mixing common general-purpose plastics, such as Niter, Henschelmi +-+)-1, and Banbury mixer/roll, the composition of the present invention has particularly low fluidity under heating. Because of its excellent properties, it can be easily and uniformly mixed and dissolved at 120 to 150°C using a simple heatable mixing container.

The injection molding machine for molding this composition can be a general one (pot-type or ram-type injection molding machines used in this case can be applied as they are, but molding machines equipped with a pre-plasticizing device, such as injection molding machines with a blend feeder) can be used. By using a molding machine (manufactured by Messai Jushi Kogyo Co., Ltd.), each raw material component is pulverized in advance and then tri-blended with the filler and fed. This eliminates the heating, melting, and mixing processes. You can also.

Molded products that can be injection molded using the asphalt composition for injection molding of the present invention range from civil engineering and architecture to household items, such as containers, pipes, flower pots, seedling boxes, decorative items (statues and other figurines), etc. It is possible to provide products for various purposes at low cost.

The present invention will be explained in more detail below with reference to Examples.

Examples 1 to 4 and Comparative Examples 1 to 4 Various asphalts and aromatic petroleum resins were weighed in the proportions shown in Table 1, and heated to 180'cc.
After kneading with a pressure kneader for about 20 minutes to prepare a uniform asphalt composition for injection molding, Danop,
Leave to cool and crush with a crusher to form a pellet.
(Ishi was made into powder.

Next (this is compression molded at 130℃ to a thickness of 3rIr!
A test plate of n was obtained.

The evaluation results using this test piece are shown in the lower part of Table 11.

The compositions of Examples 1 to 4, which are a combination of asphalt with low penetration and aromatic petroleum resin with high softening point, have an original shape retention heat resistance temperature of 70°C or higher, and have very good hardness and bending strength V. Met.

The composition of Comparative Example 1 containing a small amount of aromatic petroleum resin was deformed by its own weight the day after molding even if it was left indoors.

The composition of Comparative Example 2, which contained asphalt with high penetration, lacked hardness, and when several sheets were stacked and left to stand, the contact areas between the sheets adhered. Ta.

The composition of Comparative Example 3, which contained a large amount of asphalt (aromatic petroleum resin), emitted white smoke and odor when mixed, and when molded, it was too brittle and difficult to release from the mold, resulting in many damaged products. It came out.

The composition of Comparative Example 4 containing an aromatic petroleum resin having a low softening point was in good condition at room temperature, but was deformed by direct sunlight and the surface became sticky.

Example 5 When the assemblies of Examples 1 to 4 were molded into containers using a 3.50Z injection molding machine, the containers could be smoothly molded in about 20 seconds per cycle.

Waste from injection molded products made from these asphalt-based compositions can be collected, crushed, and reused for remolding, but since it is an inexpensive material, it can be treated by mixing it with road paving materials, or compared to general-purpose plastics. Because it burns far fewer calories, it can be incinerated along with general household waste.

Claims (1)

[Claims] 1 75-25wt% asphalt with a penetration of 40 or less,
Aromatic petroleum resin with a ring and ball softening point of 120°C or higher 25-7
Asphalt consisting of 5 wt% - aromatic petroleum resin content 1
An asphalt composition for injection molding, characterized in that it has excellent heat resistance and is hard, and is made by mixing 50 to 600 parts of an inorganic powdered photonic agent to 00 parts of the asphalt composition.