JPH0611866B2 - Thermoplastic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a thermoplastic resin composition. More specifically, the present invention relates to a thermoplastic resin composition in which the specific gravity is reduced without impairing the appearance of the thermoplastic resin, the heat insulating property is improved, and the antibacterial and antifungal properties are imparted while ensuring safety.

[Conventional technology]

Generally, a thermoplastic resin is processed into an injection molded product, a hollow molded product, a film, a sheet, a fiber, etc., due to its excellent processing characteristics and characteristics such as light weight and resistance to rust, and is used for various purposes.

On the other hand, it has been revealed in recent years that a thermoplastic resin, which has hitherto been considered not to be mold-damaged, is actually mold-molded, and it has become a sanitary problem depending on its application.

Under such circumstances, parts that require heat insulation, such as air conditioner parts and air conditioner parts, must be made by bonding foam made of polyurethane, polystyrene, polyethylene, etc. to thermoplastic resin parts for heat insulation. It is used. When imparting the antifungal effect to these foams, a certain antibacterial agent is removed, and the antibacterial agent added by heating during foaming sublimes, and the antifungal effect is completely retained at the time after foaming. There was a problem that not.

The specific antibacterial agent refers to the arsenic compound Vinadine (trade name), but the compound itself is safe, but there is concern about the safety if the compound decomposes due to an accident such as burning. And its use is limited.

On the other hand, most of the highly safe antibacterial agents typified by thiaventazole have sublimation or decomposability, and there is a problem that the antifungal effect is lost due to heating during foaming. is there.

On the other hand, by foaming the thermoplastic resin material itself that becomes the main body, it is possible to abolish the bonding of the foamed material such as polyurethane, polystyrene, polyethylene, etc., but even in such a method the sublimation of the antibacterial agent added However, the antibacterial agent for exhibiting the antifungal effect cannot be escaped, and the precipitation of the antibacterial agent on the surface of the thermoplastic resin also occurs inside the foamed cells, resulting in a significant loss of the effect.

Further, in foam molding of a thermoplastic resin, deterioration of appearance cannot be avoided due to surface roughening, resulting in a marked deterioration of product quality.

[Problems to be Solved by the Invention]

Thus, when trying to improve the heat insulating property together with the low specific gravity of the thermoplastic resin composition, it is difficult to obtain an antifungal effect, and it is impossible to avoid deterioration of the product appearance,
In order to obtain a highly safe antifungal effect, it is difficult to reduce the specific gravity and impart heat insulation.

The object of the present invention is to solve the contradictory problems of improving the heat insulating property of a thermoplastic resin composition and imparting antifungal properties, and having the properties of low specific gravity and high heat insulating properties and high safety antifungal properties,
Moreover, it is intended to provide a thermoplastic resin composition capable of obtaining a molded product having an excellent product appearance.

[Means for Solving the Problems]

The present inventors have conducted intensive research to solve the above problems. As a result, by combining a microspherical hollow body having a high pressure resistance that does not break even in various processes for obtaining a thermoplastic resin product and a fungicide, it has both a heat insulating property and an antifungal effect with a low specific gravity. . It was found that a thermoplastic resin composition can be obtained, and the present invention has been completed.

That is, the present invention is a thermoplastic resin composition obtained by blending a thermoplastic resin with a high pressure resistant fine spherical hollow body and a fungicide having excellent antifungal properties.

Further, with respect to 100 parts by weight of a thermoplastic resin which can be granulated at 250 ° C. or less, 10 to 100 parts by weight of micro-spherical hollow bodies having a compressive strength of 300 kg / cm ² or more, and a fungicide with excellent mold resistance and high safety 0 It is a thermoplastic resin composition which mix | blends 0.05 to 0.40 weight part.

The thermoplastic resin used in the present invention may be any resin that can be granulated at 250 ° C or lower, which is a temperature at which the highly safe antibacterial agent does not complete sublimation or decomposition. That is, polypropylene, polyethylene, polyvinyl chloride, and polystyrene, which are called four major general-purpose resins, including ionomer resins, E
EA resin, AS resin, AAS resin, ABS resin, ACS
Resins, EVA resins, GL resins, CPE resins, polyacetal resins, polybutadiene resins and the like are one kind or a mixture of two or more kinds.

On the other hand, polyamide resins, polycarbonates, PET resins, PBT resins, etc. are difficult to granulate at 250 ° C. or lower due to their heat resistance, and are not suitable for the constitution of the present invention.

The hollow body used in the present invention is a glass-based fine spherical hollow body, has a size that can be processed by an extruder or a molding machine, and preferably has an average particle diameter of 100 μm or less, and has a pressure resistance of 3 or less.
00Kg / cm ² or more, preferably 500 Kg / cm ² or more.

Withstand pressure strength of 300 kg / cm ² is the breaking strength due to hydrostatic pressure.
According to STMD3102, refers to those that are 10% or less destroyed.

When the compressive strength is less than 300 kg / cm ² , the hollow body is likely to be broken due to pressure and shear stress in the granulation and molding steps for obtaining a product, and as a result, the hollow body cannot maintain the hollow shape. Therefore, reduction in specific gravity and reduction in thermal conductivity cannot be achieved.

Further, it is preferable that the true specific gravity of the hollow body is in the range of 0.40 to 0.70.

In the hollow body having a true specific gravity of less than 0.40, since the wall thickness of the hollow body becomes thin, a pressure resistance of 300 kg / cm ² or more cannot be realized, and when the true specific gravity exceeds 0.70, the thermoplastic resin has a Of which
Since the specific gravity of polypropylene, which has the lowest specific gravity, is 0.90, the difference in specific gravity between the hollow body and the propylene polymer is small, and the effect of lowering the specific gravity by blending the hollow bodies is not preferable, which is not preferable.

The blending amount of the hollow body used in the present invention is 100% thermoplastic resin.
10 to 100 parts by weight is preferable relative to parts by weight, and 11
˜70 parts by weight.

When the content of the hollow body is less than 10 parts by weight, the effect of lowering the specific gravity and low thermal conductivity is small, and when the content of the hollow body is more than 100 parts by weight, the interval of the blended hollow bodies becomes small, thereby The effect of low thermal conductivity is diminished because heat is conducted between the surfaces of the body.

The antibacterial agent used in the present invention has an antifungal effect,
Furthermore, it is preferable that the material has high safety and does not have a bad influence on the human body even if it is decomposed due to an accident such as combustion. In other words, the minimum inhibitory concentration and acute oral toxicity of Aspergillus niger should be low, and there should be no risk of the generation of toxic gases such as arsenic and toxic gases even after decomposition by combustion.

That is, starting from benzimidazole thiabentazole (trade name), similarly benzimidazole-preventol OC3015, phenol-based preventol CMK, iodo-based amical AM-48, haloalkyl-based Captan, preventol A3 and Priventol A4S, alcoholic Dekabiace, heterocyclic nitrogen compound Sojumu omazine, Dencil S100
And the like, or a mixture of two or more thereof.

On the other hand, binadine is an organic arsenic compound and is not preferable because it may become an arsenic single substance which is a poisonous substance in the event of an accident such as burning.

Similarly, cyanate-based and thiocyanate-based antibacterial agents, which are liable to generate a highly toxic cyan gas in the event of an accident such as combustion, are not preferable.

Among the heterocyclic nitrogen compounds, zinc ommazine is not preferable because acute oral toxicity is as high as 200 mg / Kg in rat LD50.

In the composition of the present invention, various additives that are usually added to thermoplastic resins, for example, phenol-based, thioether-based, phosphorus-based antioxidants, light stabilizers, nucleating agents, lubricants, antistatic agents Agents, anti-fog agents, anti-blocking agents, non-dripping agents, pigments, heavy metal deactivators (copper damage inhibitors), radical generators such as peroxides, dispersants such as metal soaps, or neutralizing agents, inorganics Fillers (for example, talc, mica, clay, wollastonite, calcium carbonate, aluminum hydroxide, silicon dioxide, titanium dioxide, zinc oxide, magnesium oxide, zinc sulfide, barium sulfate, calcium silicate, aluminum silicate, glass fiber, Potassium titanate, carbon fiber, carbon black, graphite, metal fiber, etc.) or coupling agent (eg, silane type, titanate type) Boron-based, aluminate-based, can be used in combination within limits not detrimental to the object of the present invention the inorganic filler or the like which has been surface-treated with such surface treating agent of the zircoaluminate, etc.).

The composition of the present invention is a thermoplastic resin according to the present invention, the high pressure-resistant micro spherical hollow body and the antibacterial agent according to the present invention, and the above-mentioned various additives usually added to the thermoplastic resin. A low shear type mixing device such as a tumbler mixer (trade name), a ribbon blender, a hovered mixer or the like, and a conventional single-screw extruder,
With a twin-screw extruder, a Brabender, or a roll, the melt-kneading temperature is 170 ° C to 270 ° C, preferably 190 ° C to 2
It can be obtained by melt-kneading at 30 ° C. and pelletizing.

The obtained composition is used for producing a desired molded article by various molding methods such as an injection molding method, an extrusion molding method and a blow molding method.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

The evaluation methods used in Examples and Comparative Examples were as follows.

(1) Specific gravity: Using the pellets obtained, length 63.5 m
A test piece of m, width 12.7 mm, and thickness 3.2 mm was prepared by injection molding, and the specific gravity was measured using the test piece (JISK
7207) to evaluate the specific gravity.

(2) Thermal conductivity: length of 150m using the obtained pellets
A test piece with m, a width of 150 mm and a thickness of 3 mm was prepared by an injection molding method, and the thermal conductivity was measured using the test piece (ASTMD
2320; according to the probe method). A material having a good heat insulation property has a low thermal conductivity.

(3) Mold resistance: length of 50 mm using the obtained pellets,
A test piece with a width of 50 mm and a thickness of 2 mm (the thickness of the sample when a foaming agent was used was 4 mm) was prepared by injection molding, and the test piece was placed on an inorganic agar medium in a petri dish and pre-cultured Aspergillus. The mycelial growth state is observed 28 days after spraying the nutrient solution containing fungi (mold) such as niger.

(4) Remaining amount of antibacterial agent: length of 5 using the obtained pellet
A test piece having a width of 0 mm, a width of 50 mm and a thickness of 2 mm is prepared by an injection molding method, and the test piece is quantitatively analyzed by fluorescent X-ray analysis and infrared analysis for the residual amount of the antibacterial agent.

(5) Appearance: Using the obtained pellets, a test piece having a length of 50 mm, a width of 50 mm and a thickness of 2 mm is prepared by an injection molding method,
The test pieces are visually identified to rank the appearance and inferiority.

The test pieces used in each of the above tests were prepared by injection molding the obtained pellets at a resin temperature of 250 ° C and a mold temperature of 50 ° C.

Using the obtained test pieces, the specific gravity, the thermal conductivity, the antifungal property, the residual amount of the antibacterial agent and the appearance were evaluated by the above-mentioned test methods. The results are shown below.

(Examples 1 to 6 and Comparative Examples 7 to 10) As Examples 1 to 6, a polypropylene resin, which is a kind of the thermoplastic resin according to the present invention, has a pressure resistance of 700 kg / cm ² ,
A silicate glass microspheres having an average particle diameter of 25 to 30 μm and a predetermined amount of thiaventazole were placed in a tumbler mixer (trade name) in a mixing ratio shown in Table 1 below, and the mixture was stirred and mixed for 5 minutes, and then a diameter of 30 mm. 230 with a twin-screw extruder
The mixture was melt-kneaded at 0 ° C. and pelletized.

Further, as Comparative Example 7, polypropylene resin containing neither hollow body nor antibacterial agent was used. As Comparative Examples 8 and 9, polypropylene resin containing ordinary glass microspheres outside the scope of the present invention (pressure resistance of 270 kg / cm ² , average particle size 80μ
m) and the prescribed amount of thiaventazole were pelletized in the same proportions as shown in Table 1 below in the same manner as in Examples 1 to 6.

Similarly, as Comparative Example 10, the hollow body was not mixed with the polypropylene resin, and the foaming agent and thiaventazole were blended in the same proportions as shown in Table 1 below, and pelletized in the same manner as in Examples 1 to 6.

Using the obtained test pieces, the specific gravity, the thermal conductivity, the antifungal property, the residual amount of the antibacterial agent and the appearance were evaluated by the above-mentioned test methods. The results are shown in Table 1.

Test pieces used for evaluation of specific gravity, thermal conductivity, antifungal property, residual amount of antibacterial agent and appearance were prepared by injection molding the obtained pellets at a resin temperature of 250 ° C and a mold temperature of 50 ° C.

(Examples 11 to 15 and Comparative Examples 16 to 19) As Examples 11 to 15, a high-density polyethylene resin, which is a kind of the thermoplastic resin according to the present invention, has a compressive strength of 700.
Kg / cm ² , average particle diameter 25 to 30 μm, silicate glass microspheres and thiaventazole were mixed in a tumbler mixer (trade name) at a mixing ratio shown in Table 2 below for 5 minutes. Then, the mixture was melt-kneaded at 200 ° C. with a twin-screw extruder having a diameter of 30 mm to form pellets.

Further, as Comparative Example 16, a high-density polyethylene resin containing neither a hollow body nor an antibacterial agent, Comparative Examples 17 and 18
As a high density polyethylene resin, an ordinary glass-based micro spherical hollow body (withstand pressure strength of 270 kg / cm ² , which is outside the scope of the present invention,
Pelletization was carried out in the same manner as in Examples 11 to 15 with an average particle size of 80 μm) and a predetermined amount of thiaventazole at the compounding ratios shown in Table 2 below.

Similarly, as Comparative Example 19, the hollow body was not blended in the high-density polyethylene resin, and the blowing agent and the predetermined amount of thiabentazole were pelletized in the same proportions as in Examples 11 to 15 at the blending ratios shown in Table 2 below.

By the above test method using the obtained test piece, specific gravity,
The thermal conductivity, mold resistance, and appearance were evaluated.

The results are shown in Table 2.

Test pieces used for evaluation of specific gravity, thermal conductivity, antifungal property, residual amount of antibacterial agent and appearance were prepared by injection molding the obtained pellets at a resin temperature of 250 ° C and a mold temperature of 50 ° C.

As can be seen from Table 1, Examples 1 to 6 are examples in which polypropylene is used as the thermoplastic resin and high pressure resistant glass microspheres within the constitution range of the present invention and thiaventazole as a bacteriostatic agent are blended. Yes, Comparative Example 7 is an example in which neither the hollow body nor the antibacterial agent was blended, and Examples 1 to 6 have specific gravities with respect to Comparative Example 7 which is a normal polypropylene prescription agent.
It can be seen that the decrease in thermal conductivity and the antifungal effect are clearly superior.

Comparative Examples 8 and 9 have a pressure resistance of 27, which is outside the scope of the present invention.
This is an example using a hollow body of 0 kg / cm ² , and other formulations are the same as those in Examples 3 and 5.

According to this, it is clear that Comparative Examples 8 and 9 bring about an increase in specific gravity and thermal conductivity in spite of using the hollow body as compared with Examples 3 and 5, and the appearance is also in Examples 3 and 5. It's worse than No. 5. This indicates that the hollow body having a pressure-resistant strength of 270 kg / cm ² used in the comparative example was destroyed at the stage of granulation and injection molding, and it is not preferable for the hollow body having a normal pressure-resistant strength.

Comparative Example 10 is an example of trying to reduce the specific gravity and the thermal conductivity by adding a foaming agent instead of the hollow body.

As the antibacterial agent, the same amount of thiaventazole as in Examples 1, 3, 5 and 6 was blended and compared with the examples. According to this, although the effects similar to those of the examples are obtained in terms of specific gravity and thermal conductivity, there is almost no effect on mildew resistance, and the appearance is remarkably inferior.

Regarding mold resistance, since the antibacterial agent was sublimated or decomposed during foaming, and the antibacterial agent was precipitated in the bubbles in the polypropylene resin generated by foaming, the amount of precipitation on the resin surface was relatively reduced. , It is considered that the antifungal property has been reduced.

In any case, it is clear that the method using the foaming agent cannot obtain the thermoplastic resin having the low specific gravity and the improved heat insulating property and antifungal property without impairing the appearance which is the object of the present invention. Is.

In Table 2, polyethylene was used instead of polypropylene as the thermoplastic resin, and the other formulations were the same as those in Table 1.

Examples 11, 12, 13, 14, 15 in Table 2 correspond to 1, 2, 3, 4, 6 in Table 1, and Comparative Examples 16, 17, 1
8,19 correspond to 7,8,9,10.

The results are the same as in Table 1.

That is, in the conventionally known thermoplastic resin composition, it is difficult to secure high external appearance and mildewproofness in order to secure low specific gravity and heat insulation properties, and it is difficult to secure mildewproofness in low specific gravity. It will be difficult to obtain heat resistance and heat insulation.

From this, the composition of the present invention has appearances and low specific gravity which are not known in conventional thermoplastic resin compositions, heat insulating properties and antibacterial properties, and antifungal properties, which are contradictory features to be realized,
It was found that the composition of the present invention was remarkably excellent in that it was used together at a high level, and the remarkable effect of the composition of the present invention was confirmed.

[Effect of the Invention] The composition of the present invention is a conventionally known thermoplastic resin composition obtained by blending a foaming agent with a conventional thermoplastic resin, and a thermoplastic resin composition obtained by incorporating a bacteriostatic agent. Compared with a thermoplastic resin composition, it is possible to improve practical strength by reducing the weight of a molded product or obtaining a molded product having a larger wall thickness with the same weight while maintaining excellent heat insulation and appearance. ,
Moreover, the mutually conflicting requirements that a safe and reliable antifungal effect can be obtained can be realized at the same time.

This paved the way for the development of new applications for thermoplastic resins, and the effect is great.

Claims (1)

[Claims] 1. A thermoplastic resin 1 which can be granulated at 250 ° C. or lower.
To 100 parts by weight, 10 to 100 parts by weight of micro-spherical hollow bodies having a pressure resistance of 300 kg / cm ² or more and 0.05 to 0.40 part by weight of a highly safe antibacterial agent are mixed. Thermoplastic resin composition.