JPH0819321B2 - Plastic clay - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a resin composition having a controlled softening temperature and curing rate, and a plastic clay. More specifically, it relates to a resin composition and a plastic clay having a softening temperature of 40 ° C. to 60 ° C., which is obtained by uniformly mixing thermoplastic polycaprolactone and chlorinated polyethylene.

(Prior Art) Conventionally, clay has been widely used by art lovers, but recently, it has also been widely used as teaching materials for school children and toys for infants.

However, such a clay is extremely difficult to correct in the event of failure in the modeling process, and depending on the degree of failure, it has often been necessary to redo the modeling using a new material.

Further, the finished product has a defect that cracks are generated due to drying, and if it is dropped, it is easily broken, and the details of the shaped object are easily collapsed even by a light shock, and cracks are easily generated.

Also, when kneading by hand, clay adheres to the hands from beginning to end, which not only causes dirt and loss of clay, but also
There is also a problem that when dried, dust is generated.

Furthermore, since it takes a considerable amount of time for the work to dry, it is difficult to manage during that time.

In addition, even when the finished work is colored using a paint, a poster color, or the like, it is difficult to uniformly and beautifully finish the surface if the surface is insufficiently polished or cracks are generated.

It is also difficult to knead pigments and dyes for coloring, and it is impossible to color the entire surface beautifully.

As an improvement over the above points, a clay using a polycaprolactone composition is disclosed in JP-A-61-42679.

However, the polycaprolactone resin disclosed in the above publication is not sufficient in the following points.

(Problem to be Solved by the Invention) One of the problems is a softening temperature.

Since polycaprolactone does not soften unless it is kept at a temperature of at least 60 ° C, it had to be shaped after being softened by boiling water at 60 ° C or higher, usually about 80 ° C.

The need to use boiling water at 80 ° C can cause burns, especially for school children and infants.

Further, since the time until hardening was too short, there was not enough time to make the work, and the work was often hardened during the making and had to be soaked in hot water again to be softened.

In view of such a situation, the present inventors have made intensive studies and completed the present invention.

(Structure of the invention) That is, the present invention relates to "a plastic comprising a resin composition characterized in that a polycaprolactone resin having a relative viscosity of 1.15 to 2.80 and chlorinated polyethylene are blended at a weight ratio of 50/50 to 95/5. It is clay.

This composition is suitable as a plastic clay because it softens between 40 ° C. and 60 ° C., and after the softening, the curing time when molding at room temperature is convenient.

The caprolactone composition used in the present invention can be obtained by reacting an ordinary caprolactone monomer in the presence of a catalyst using water in the monomer as an initiator.

In the case of producing a polymer having a small molecular weight, an initiator such as ethylene glycol may be added in some cases.

As the catalyst used in this reaction, an organic tin compound, an organic titanium compound, an organic tin halide compound, etc. are generally used. Add 0.1 to 5000 ppm, and polymerize at 100 to 230 ° C, preferably in an inert gas. A polycaprolactone resin can be obtained.

This polycaprolactone composition has various degrees of polymerization from a liquid state to a solid state at room temperature, and is used for various purposes. It is desirable to use a thermoplastic polycaprolactone composition whose degree is in a certain range.

That is, a polycaprolactone polymer having a relative viscosity of 1.50 to 2.80 is preferably used.

The relative viscosity referred to in the present invention is a viscosity measured using a capillary viscometer (Ubbelohde viscometer).

 The measurement was performed according to JIS K6726.

However, the concentration of toluene as solvent is 1% and the temperature is 25.00 ± 0.05.
Take the value measured at ° C.

On the other hand, chlorinated polyethylene is preferably obtained by chlorinating polyethylene or a copolymer of ethylene and another vinyl monomer, having a chlorination rate of 25% to 45% and being non-crystalline.

The non-crystalline material described in the present invention means that the melting peak measured by a differential thermal analyzer (DSC) is 3 cal / g or less.

If the non-crystallinity of the ethylene portion remains in the chlorinated polyethylene, the polyethylene crystals do not melt even at the temperature at which the polycaprolactone crystals melt, which makes the shaping difficult.

The method for uniformly mixing polycaprolactone and chlorinated polyethylene is not particularly limited, but an extruder,
Melt kneading with a kneader, a Hanbury mixer, etc. can be exemplified.

The suitable blending ratio of polycaprolactone resin and chlorinated polyethylene is 50/50 to 95/5. If the blending ratio of chlorinated polyethylene is less than 5%, the effects of lowering the softening temperature and delaying the curing rate are insufficient.

On the other hand, if it exceeds 50%, uniform mixing is difficult, and even if the mixing is uniform, the curing time becomes too long, and molding becomes difficult.

Further, there is a disadvantage that the clay adheres to the hand when softened.

Here, the blending ratio of chlorinated polyethylene and the softening temperature,
There is a strong correlation between the effect of retarding the cure rate.

That is, the larger the blending ratio of chlorinated polyethylene, the lower the softening temperature and the slower the curing rate.

Therefore, it is possible to control the softening temperature and the curing time by changing the blending ratio of chlorinated polyethylene according to the purpose of use.

The curing rate can be controlled not only by the blending ratio of chlorinated polyethylene but also by the molecular weight of polycaprolactone.

Curing of this composition is achieved by crystallization of polycaprolactone, but in monodisperse polycaprolactone having a relative viscosity in the range of 1.50 to 2.80, the lower the molecular weight, the faster the crystallization rate.

On the other hand, the lower the molecular weight, the lower the impact resistance, and the harder it is to use as clay.

By combining the above principles, it is possible to obtain a composition having a low softening temperature and a too low curing rate.

That is, the blending ratio of chlorinated polyethylene is set to 5% or more and 50% or less so that the softening temperature is 50 ° C or less.

The polycaprolactone resin to be blended with this should preferably have a relative viscosity of 1.15 to 2.80.

Furthermore, in order to increase the crystallization speed, the relative viscosity is 1.15 to 1.
50 components, 1.50-2.80 to further improve impact resistance
It is preferable to use a blend of the above components.

The curing rate can also be increased by adding a crystal nucleating agent for the polycaprolactone resin. That is, when the chlorinated polyethylene is blended in a large amount and the softening temperature is lowered, the curing time is excessively extended.
It can be prevented by mixing a crystal nucleating agent.

Here, as a crystal nucleating agent for polycaprolactone, a general polyester nucleating agent is effective.

Examples thereof include sodium stearate, calcium stearate, magnesium stearate, calcium carbonate, magnesium carbonate, talc, clay, mica, titanium oxide, lithium fluoride, and polyethylene terephthalate powder.

Particularly, since the metal salt of higher fatty acid also acts as a lubricant at the same time, the problem of sticking to the hand when softened can be solved at the same time.

For these compositions, if necessary, color tone, strength, stability, various coloring substances, fillers,
A stabilizer for chlorinated polyethylene or polycaprolactone may be mixed.

When the composition thus obtained is used as a plastic clay, it can be molded into a pellet, a strand, a sheet, a lump, or a free shape such as being preformed.

 The effects of the present invention will be described below with reference to examples.

(Example 1) Commercially available polycaprolactone resin as polycaprolactone H5 (manufactured by Daicel Chemical Industries, Ltd .: relative viscosity 2.34) is used as chlorinated polyethylene, elastrene.
20% by weight of 408A (Showa Denko KK: chlorination rate 40%) at 120 ° C using Brabender Plastograph
Kneaded for 0 minutes.

DSC of the obtained sample (DSC manufactured by PerkinElmer, Inc.)
Table 1 shows the onset temperature of the melting peak and the crystallization peak temperature at −2C).

(Example 2) Blending was carried out in exactly the same manner as in Example 1 except that the blending ratio of elastrene 408A, which is a chlorinated polyethylene, was 7%.

 Table 1 shows the DSC result of the obtained sample.

(Example 3) Blending was carried out in exactly the same manner as in Example 1 except that the blending ratio of 408A of elastrene, which is a chlorinated polyethylene, was set to 40%.

 Table 1 shows the DSC result of the obtained sample.

(Example 4) Polycaprolactone H1 as polycaprolactone resin
(Daicel Chemical Industry Co., Ltd., relative viscosity 1.28) is 30% by weight, Polycaprolane H7 (Daicel Chemical Industry Co., Ltd., relative viscosity 2.34) is 30%, Erasulene 408A 40% as chlorinated polyethylene, Brabender Plus Kneading was performed at 120 ° C for 10 minutes using the graph.

Table 1 shows the onset temperature and the crystallization peak temperature of the melting peak of the obtained sample.

(Example 5) To 100 parts by weight of the sample obtained in Example 3, 5 parts by weight of calcium stearate (manufactured by Nakai Chemical Co., Ltd.) was added, and 120 ° C by Brabender Plastograph.
For 5 minutes.

 Table 1 shows the DSC result of the obtained sample.

(Example 6) Chlorinated paraffin 303 (manufactured by Showa Denko KK: chlorination rate 3 as chlorinated polyethylene instead of Erasulene 408A)
Blending was performed in exactly the same manner as in Example 1 except that 0%) was used.

 The results of DSC are shown in Table-1.

(Comparative Example 1) Commercially available polycaprolactone resin polycaprolactone H5
The results of DSC of (Daicel Chemical Industries, Ltd .: relative viscosity 2.34) are shown in Table 1.

(Comparative Example 2) Blending was carried out in exactly the same manner as in Example 1 except that the blending ratio of elasulene 408A which was chlorinated polyethylene was 3%.

 Table 1 shows the DSC result of the obtained sample.

(Comparative Example 3) Blending was carried out in exactly the same manner as in Example 1 except that the blending ratio of the chlorinated polyethylene, Eraslen 408A, was set to 60%.

 Table 1 shows the DSC result of the obtained sample.

(Explanation of DSC) DSC-2C manufactured by PerkinElmer was used for DSC measurement.

 Temperature correction was performed using n-octane.

The melting behavior was measured at a heating rate of 20 ° C./min, and the onset temperature of the endothermic peak is shown in Table 1.

This temperature is the minimum temperature at which the plastic viscosity softens.

35 ℃ or more and less than 58 ℃ is suitable, preferably 35 ℃ or more 55
It is less than ℃.

The crystallization behavior was measured at a cooling rate of 5 ° C./min, and the peak temperature of the exotherm is shown in Table 1.

If this temperature is 30 ° C or higher, the curing time is short and molding is not easy, and if it is 0 ° C or lower, the curing time is too long.

Claims (6)

[Claims] 1. A plastic clay comprising a resin composition, which is obtained by blending polycaprolactone resin with chlorinated polyethylene in a weight ratio of 50/50 to 95/5. 2. A polycaprolactone resin having a relative viscosity of 1.15 to 1.
A plastic clay comprising the resin composition according to claim (1), which has 2.80. 3. A polycaprolactone resin having a relative viscosity of 1.15 to 1.
A plastic clay comprising the resin composition according to claim (1), which is a blend of one having 1.50 and one having a relative viscosity of 1.50 to 2.80. 4. A plastic clay comprising the resin composition according to claim 1, wherein the resin composition contains a metal salt of a higher fatty acid. 5. The chlorinated polyethylene has a chlorine content of 25 to 45%.
A plastic clay comprising the resin composition according to claim (1), which is amorphous. 6. A plastic clay comprising the resin composition according to claim 1 or 4, wherein the fatty acid metal salt is calcium stearate.