JP2001220467A - Composition for molding processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain resin composition having low heat of combustion and good flowability and intended for molding processing use. SOLUTION: The resin composition for molding processing is obtained by admixing >50 wt.% but <=70 wt.% of a starch-based low heat combustion heat component with >=30 wt.% but <50 wt.% of a high combustion heat component based on a thermoplastic synthetic resin higher in combustion heat than starch, wherein the above starch has a particle size of 5-150 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a molding composition used for molding such as injection molding, extrusion molding, and melt compression molding.

[0002]

2. Description of the Related Art A resin composition for molding and processing mainly comprising a thermoplastic synthetic resin is known. The resin composition is processed into a molded product such as a sheet or a container by utilizing techniques such as injection molding, extrusion molding, and melt compression molding. The discarded molded product is incinerated in an incinerator at a waste cleaning plant. However, synthetic resin has a high heat of combustion per unit weight, causing damage to the incinerator. As a means for reducing the heat of combustion of a molded article, there is a technique of incorporating paper into a thermoplastic synthetic resin.

Japanese Patent Application Laid-Open No. Hei 10-138241 discloses that a thermoplastic synthetic resin contains a paper component obtained by shredding a composite paper having a polyethylene resin layer mainly on both sides or one side. Low density polyethylene,
Linear low-density polyethylene, at least one resin of medium-density polyethylene and high-density polyethylene, and a shredded resin component obtained by shredding any one of at least one resin of metallocene-polyethylene. The disclosed paper-containing resin pellets are disclosed.

[0004] The paper-containing resin pellet has a paper component content of 50% by weight or more, and the difference between the specific gravity of the paper shredder component and the specific gravity of the shredded resin component is ± 0.05 to ± 0.16 g / cm. It is in the range of ³ . By using shredded paper components having a resin layer on both sides or one side, paper-containing resin pellets can be uniformly dispersed when the paper component and the resin component are kneaded, and the pellets of those components can be dispersed. Can be prevented. Paper-containing resin pellets are 1 mm square
The shredded paper component cut into 5 mm squares and the shredded resin component cut into 1 mm to 5 mm squares are heated and kneaded by a kneading machine, and then extruded by an extruder to produce.

[0005]

The paper-containing resin pellets disclosed in the above publication use shredded paper components of 1 mm square to 5 mm square, so that the paper components are kneaded with the resin components in the form of short fibers. In addition, since the content of the paper component accounts for a majority of 50% by weight or more, the paper component that does not show fluidity even when heated interferes with the fluidity of the resin component.

When a paper-containing resin pellet is used for injection molding, it is necessary to inject the paper-containing resin at a high temperature, a high pressure, and a high speed because the flow resistance of the paper-containing resin is high and the resin is easily solidified. However, when the melting temperature of the resin exceeds about 190 ° C., the paper component contained in the resin is thermally decomposed, so that the temperature cannot be further increased. If the resin flows into the mold at high temperature and high pressure, the injection molding machine and the mold may be damaged.

SUMMARY OF THE INVENTION An object of the present invention is to provide a composition having low heat of combustion and good fluidity. In the case of injection molding using the composition, it is not necessary to inject the composition at a high temperature, a high pressure and a high speed. An object of the present invention is to provide a composition for molding that can produce a molded article such as a container.

[0008]

According to the present invention, there is provided a low-combustion heat component containing starch as a main component.
An object of the present invention is to improve a molding composition obtained by mixing a high-combustion heat component whose main component is a thermoplastic synthetic resin whose combustion heat is higher than that of the starch, and which is obtained by mixing these components.

According to a feature of the present invention, the starch has a particle size of 1 to 100 μm, and the composition comprises
It contains more than 50% by weight and 70% by weight or less of the low combustion heat component, and 30% or more and less than 50% by weight of the high combustion heat component. Weight% of high combustion heat component is low combustion heat component>
It is in the relation of high combustion heat components.

In one embodiment of the present invention, the high-combustion heat component is selected from the group consisting of thermoplastic elastomer, hydrogenated styrene-butadiene rubber, styrene-ethylenebutylene / olefin crystal block copolymer, olefin crystal / ethylenebutylene / olefin crystal. A thermoplastic modifying component formed from at least one of the block copolymers, wherein the modifying component accounts for at least 3 wt% and at most 20 wt% of the weight percent of the high combustion heat component. ing.

As another example of the embodiment of the present invention,
The low-combustion heat component is a paper powder having a particle size of 50 μm or more and 200 μm or less, and at least one of a powdered inorganic substance of titanium oxide, talc, calcium carbonate, calcium sulfate, barium sulfate, and kaolin. Wherein the paper powder accounts for 10% by weight or more and 30% by weight or less of the low-burning heat component by weight, and the inorganic substance accounts for 1% by weight of the low-burning heat component.
% Of the starch, the paper powder, and the inorganic material, and the starch, the paper powder, and the inorganic material have any relationship of starch> paper powder or inorganic material, and starch> paper powder + inorganic material.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the composition for molding according to the present invention are as follows.

(1) A composition shown as an example (hereinafter referred to as a first composition)
It is called a composition. ) Is composed of a low combustion heat component mainly composed of starch and a high combustion heat component mainly composed of a thermoplastic synthetic resin whose combustion heat is higher than that of starch. First
The composition contains 50% by weight of starch which forms a low combustion heat component.
And the synthetic resin forming the high combustion heat component is contained in the range of 30% by weight or more and less than 50% by weight, and the starch and the synthetic resin in the first composition are contained in the first composition. % By weight of starch> synthetic resin. Starch has a particle size in the range of 1 to 100 μm.

Synthetic resins include low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, metallocene-polyethylene, block-polymerized polypropylene, random-polymerized polypropylene, homo-polymerized polypropylene, metallocene-polypropylene, olefin-based elastomer, ethylene vinyl Acetate copolymer, ethylene ethyl acrylate copolymer, styrene
Acrylonitrile copolymer (AS resin), polybutadiene-styrene-acrylonitrile graft copolymer (A
(BS resin), polystyrene, polyvinyl chloride, or a mixture of two or more of these resins.

If the amount of the starch exceeds 70% by weight and the amount of the synthetic resin is less than 30% by weight, the starch which does not show fluidity even when heated significantly lowers the fluidity of the synthetic resin. It is difficult to obtain good fluidity in the product. When the amount of starch is less than 50% by weight and the amount of synthetic resin is 50% by weight or more, the synthetic resin which is a high combustion heat component occupies the majority of the composition. Hindered and can only slightly reduce the heat of combustion of the composition.

If the particle size of the starch is less than 1 μm, a plurality of steps are required to process the starch to a particle size of less than 1 μm, which increases the production cost of the starch used. As a result, the production cost of the composition or a molded article using the composition increases.

If the particle size of the starch exceeds 100 μm, the starch may cause poor dispersion in the synthetic resin, and the starch may form a bulky substitute in the synthetic resin. The fluidity of the composition may be significantly reduced.

Among the 100% by weight of the first composition, starch having a particle size in the range of 1 μm ≦ particle size ≦ 100 μm as a low combustion heat component is contained in the range of 50% by weight <starch ≦ 70% by weight. As a result, the heat of combustion of the composition can be reduced, and the composition has good fluidity.

(2) Another example of a resin composition (hereinafter, referred to as a second composition) is a low-combustion heat component containing starch as a main component, a thermoplastic synthetic resin as a main component, and a thermoplastic resin. And a high combustion heat component containing a reforming component. The second composition contains 5% starch which forms a low combustion heat component.
More than 0% by weight and 70% by weight or less, and a mixture of a synthetic resin and a modifying component forming a high combustion heat component in a range of 30% by weight or more and less than 50% by weight. The starch and the synthetic resin are the same as those of the first composition.

The modifying component has mutual affinity with the synthetic resin, and can form a mixture with the synthetic resin to improve the fluidity of the synthetic resin. Further, the modifying component has a function as a binder for bonding the synthetic resin and the starch. The reforming component accounts for 3% of the total weight of the high combustion heat component.
It accounts for not less than 20% by weight and not less than 20% by weight. The modified component has a melt flow index of 10 to 25 g / 1.
It is in the range of 0 minutes.

The modifying component may be any one of a thermoplastic elastomer, hydrogenated styrene-butadiene rubber, styrene-ethylenebutylene / olefin crystal block copolymer, olefin crystal / ethylenebutylene / olefin crystal block copolymer, or a mixture thereof. Are blended in two or more types.

Hydrogenated styrene-butadiene rubber, styrene-ethylene butylene / olefin crystal block copolymer, and olefin crystal / ethylene butylene / olefin crystal block copolymer are highly random copolymers formed from ethylene and butene-1. This is a polyolefin-based thermoplastic synthetic resin that has no double bond in the polymer molecule, has low crystallinity, is flexible and has high transparency.

When the content of the modifying component is less than 3% by weight and the melt flow index of the modifying component is less than 10 g / 10 minutes, the modifying component does not act sufficiently and improves the fluidity of the second composition. I can't let it. If the modifying component exceeds 20% by weight and the melt flow index of the modifying component exceeds 25 g / 10 minutes, the second composition is softened more than necessary. However, sufficient hardness cannot be obtained. Further, the tensile strength and the tear strength of the composition are reduced.

(3) Another example of a starch-containing resin composition (hereinafter referred to as a third composition) is a starch-based resin composition containing a low-combustion heat component containing paper powder and a thermoplastic synthetic resin. It is composed of a high combustion heat component as a main component. The third composition contains a mixture of starch and paper powder that forms a low combustion heat component in a range of more than 50% by weight and 70% by weight or less, and 30% of a synthetic resin that forms a high combustion heat component.
% By weight and less than 50% by weight. The starch and the synthetic resin are the same as those of the first composition.

[0025] Paper powder has a lower ignition point when incinerated than that of starch, and by adding paper powder to the composition, the composition can be burned with low heat. Paper powder accounts for 10% by weight or more and 30% by weight or less of the total weight% of the low combustion heat component, and the weight percentage of starch and paper powder is in a relationship of starch> paper powder.

The paper powder is prepared by using at least one of hardwood pulp and softwood pulp as a raw material, and then pulp is pulverized into a powder and cellulose is used, and waste paper is pulverized into a powder. Or a combination of both. It is preferable that the lignin component is 1% or less for the hardwood pulp and the softwood pulp as the raw material, and the paper powder that is made of the waste paper is 95% by weight or more of the cellulose component. preferable. Paper powder has a particle size of 50 μm or more and 200 μm or less, preferably 75 μm or less.
m or more and 150 μm or less.

When the content of the paper powder is less than 10% by weight, the effect of lowering the ignition point of the composition is small. If the amount of the paper powder exceeds 30% by weight, the proportion of the paper powder having a higher heat of combustion than starch increases, so that the heat of combustion of the composition increases.

If the particle size of the paper powder is less than 50 μm, a plurality of steps are required to process the paper powder to a particle size of less than 50 μm, which increases the production cost of the paper powder used. Particle size of paper powder is 20
If it exceeds 0 μm, the paper powder may cause poor dispersion in the synthetic resin, and the paper powder may form a bulky flour in the synthetic resin. It may be significantly reduced.

(4) Another example of a starch-containing resin composition (hereinafter referred to as a fourth composition) is a low-combustion heat component containing starch as a main component and containing a powdery inorganic material, and a thermoplastic synthetic resin. It is composed of a high combustion heat component containing a resin as a main component. The fourth composition contains more than 50% by weight and more than 70% by weight of a mixture of starch and an inorganic material forming a low combustion heat component.
In the following range, the synthetic resin forming the high combustion heat component is contained in the range of 30% by weight or more and less than 50% by weight. The starch and the synthetic resin are the same as those of the first composition.

The inorganic substance accounts for 1% by weight or more and 20% by weight or less of the total weight% of the low combustion heat component, and the weight% of the starch and the inorganic substance has a relation of starch> inorganic substance. The inorganic substance is one of titanium oxide, talc, calcium carbonate, calcium sulfate, barium sulfate, and kaolin.
Kind or a mixture of two or more of these inorganic substances. Since inorganic substances are nonflammable, the heat of combustion of the composition can be further reduced by adding the inorganic substance to the composition.

When the amount of the inorganic substance is less than 1% by weight, the inorganic substance does not sufficiently act, and the effect of lowering the heat of combustion of the composition is small. When the amount of the inorganic substance exceeds 20% by weight, the plasticity, ductility, and impact resistance of the composition may be extremely reduced.

(5) As another example, a starch-containing resin composition (hereinafter referred to as a fifth composition) comprises a starch-based low-combustion heat component containing paper powder and a thermoplastic synthetic resin. It is composed of a high combustion heat component containing a reforming component as a main component. The fifth composition comprises a mixture of starch and paper powder forming a low combustion heat component in a range of more than 50% by weight and 70% by weight or less, a synthetic resin forming a high combustion heat component and a modifying component. Is contained in the range of 30% by weight or more and less than 50% by weight. The starch, paper powder, synthetic resin, and modifying components are the same as those of the first to third compositions.

The reforming component accounts for 3% by weight or more and 20% by weight or less of the total weight% of the high combustion heat component. Paper powder accounts for 1% of the total weight percent of low-burning heat components.
It accounts for 0% by weight or more and 30% by weight or less, and the weight% of starch and paper powder is in the relationship of starch> paper powder.

(6) A starch-containing resin composition shown as another example (hereinafter referred to as a sixth composition) has a low-combustion heat component containing starch as a main component and containing a powdery inorganic material, and a thermoplastic synthetic resin. It is composed of a high combustion heat component containing a resin as a main component and a modifying component. The sixth composition contains a mixture of starch and an inorganic substance forming a low combustion heat component in a range of more than 50% by weight and less than 70% by weight, and a mixture of a synthetic resin forming a high combustion heat component and a modifying component. The mixture is contained in the range of 30% by weight or more and less than 50% by weight. The starch, the inorganic substance, the synthetic resin, and the modifying component are the same as those of the first, second, and fourth compositions.

The reforming component accounts for 3% by weight or more and 20% by weight or less of the total weight% of the high combustion heat component. The inorganic substance accounts for 1% by weight or more and 20% by weight or less of the total weight% of the low combustion heat component, and the weight% of the starch and the inorganic substance has a relation of starch> inorganic substance.

(7) A starch-containing resin composition (hereinafter referred to as a seventh composition) shown as another example is a low-combustion heat component containing starch as a main component, paper powder and a powdery inorganic substance, It has a high combustion heat component containing a thermoplastic synthetic resin as a main component. The seventh composition contains a mixture of starch, paper powder, and an inorganic substance that forms a low combustion heat component in an amount exceeding 50% by weight and 70% by weight or less, and a synthetic resin that forms a high combustion heat component in an amount of 30% by weight. % Or more and 50% by weight
It is included in the range of less than. The starch, paper powder, inorganic material and synthetic resin are the same as those of the first, third and fourth compositions.

Paper powder accounts for 10% by weight or more and 30% by weight or less of the total weight% of the low combustion heat component. The inorganic material accounts for 1% by weight or more and 20% by weight or less of the total weight% of the low combustion heat component. The weight percentage of starch, paper powder and inorganic matter is starch> paper powder +
They are related to inorganic substances.

(8) Another example of a starch-containing resin composition (hereinafter referred to as an eighth composition) is a low-combustion heat component containing starch as a main component and containing paper powder and a powdery inorganic substance. And a high combustion heat component containing a thermoplastic synthetic resin as a main component and a modifying component. In the eighth composition, a mixture of starch, paper powder, and an inorganic substance that forms a low combustion heat component is in a range of more than 50% by weight and 70% by weight or less, and a synthetic resin that forms a high combustion heat component and modified. The mixture with the component is contained in the range of 30% by weight or more and less than 50% by weight. The starch, paper powder, inorganic substance, synthetic resin, and modifying component are the same as those of the first to fourth compositions.

The reforming component accounts for 3% by weight or more and 20% by weight or less of the total weight% of the high combustion heat component. Paper powder accounts for 1% of the total weight percent of low-burning heat components.
It accounts for 0% by weight or more and 30% by weight or less. The inorganic material accounts for 1% by weight or more and 20% by weight or less of the total weight% of the low combustion heat component. The weight% of starch, paper powder and inorganic matter has a relationship of starch> paper powder + mineral matter.

In the fifth to eighth compositions, the reason for defining the weight percentage of each of starch, paper powder, inorganic substance, synthetic resin, and modifying component constituting these compositions is that those of the first to fourth compositions. Is the same as In the fifth, sixth, and eighth compositions, the melt flow index of the modifying component is equal to the second
It is identical to that of the composition.

The fifth and sixth compositions containing the modifying component, paper powder or inorganic substance and the seventh and eighth compositions containing the modifying component, paper powder and inorganic substance are the first and second compositions. The composition can further reduce the heat of combustion of the composition, and can further improve the fluidity of the composition as compared with the first, third, and fourth compositions.

The first, third and fourth compositions are composed of 1 to
10 g / 10 min, 2nd, 5th, 6th, 7th, 8th
The composition has a melt flow index ranging from 3 to 12 g / 10 minutes. The second, fifth, sixth, seventh, and eighth compositions contain the modified component in the range of 3% by weight <the modified component <20% by weight of the total weight% of the high combustion heat component. Therefore, the value of the melt flow index is higher than that of the first, third, and fourth compositions containing no modifying component.

The melt flow index of these compositions was as follows: the temperature of the first to seventh compositions was 190 ° C., the extrusion pressure was 21.18 N, the extrusion time was 10 minutes, and the composition was extruded from an orifice having a specified diameter and length. It was measured.

The first to seventh compositions are heated and kneaded by a kneader with a high-combustion heat component and a low-combustion heat component, and then formed into pellets using an extruder and a die. It is formed into a plate or lump. The first to seventh compositions are processed into molded articles such as sheets and containers using techniques such as injection molding, extrusion molding, and melt compression molding.

As used paper, used newspaper paper, used magazine paper, used printing paper, used packaging paper, used corrugated paper, used OA paper, and the like can be used. Used paper is recycled into pulp through the steps of used paper → disintegration → steaming → selection → washing and separation → bleaching → washing → deinking, waste paper → sorting → disintegration → selection → washing, etc.

[0046]

EXAMPLES A sample was prepared by mixing a low-combustion heat component and a high-combustion heat component, and the calorie (J / g), flexural modulus (MPa), and Izod impact value of the solidified composition during combustion. “23 ° C.” (kJ / m ² ) and the fluidity (L / T) for the melted composition were measured. The fluidity (L / T) was measured using a fluid flow test mold having a width of 10.0 mm and a thickness of 1.0 mm.
It measured on conditions of ° C and injection pressure (1000MPa). Here, L indicates the flow distance of the sample, and T indicates the thickness of the sample. The following four types were prepared as samples.

(1) Sample 1: A composition in which a low combustion heat component (52% by weight of starch, 3% by weight of titanium oxide) and a high combustion heat component (45% by weight of polypropylene) are mixed. (2) Sample 2: Low combustion Composition in which heat component (starch 40% by weight, paper powder 15% by weight) and high combustion heat component (45% by weight of polypropylene) are mixed. (3) Sample 3: Low combustion heat component (starch 45% by weight, titanium oxide) 10% by weight) and high combustion heat component (polypropylene 40)
(4) Sample 4: Low combustion heat component (starch 28% by weight, paper powder 21% by weight, titanium oxide 5% by weight) and high combustion heat component (5% by weight, modified component 5% by weight) Composition containing 41% by weight of polypropylene and 5% by weight of a modifying component). The measurement results are shown in Table 1.

[0048]

[Table 1]

The calorie combustion (total heat generation) of polypropylene is about 49,000 (J / g). However, in the samples 1 to 4 in which low combustion heat components are mixed with polypropylene, the combustion calories (total heat generation) are as follows. Amount) is about 25,000-2
It is 7,000 (J / g), and it can be seen that each of the calories burned by the composition is reduced. During the combustion of the compositions in the examples, white smoke was generated, but no black smoke was generated. Further, benzene and ammonia are not generated in the combustion gas.

[0050]

According to the composition for molding according to the present invention, the heat of combustion during incineration of the composition can be reduced as compared with the composition formed of a thermoplastic synthetic resin. Therefore, it does not damage the incinerator. The composition is
Since the melt flow index is in the range of 1 to 10 g / 10 minutes and has excellent fluidity, there is no need to inject the composition at high temperature, high pressure, and high speed in injection molding using the composition, and the sheet or container can be used. Etc. can be manufactured. Further, the composition can be smoothly filled in the mold, and occurrence of short mold in the mold can be prevented. There is no need to inject the composition into the mold at high pressure and high speed, so that the injection molding machine and the mold are not damaged.

The composition composed of starch and a thermoplastic synthetic resin can reduce the heat of combustion during incineration of the composition and has good fluidity. In the composition to which the modifying component is added in addition to the starch and the thermoplastic synthetic resin, the fluidity can be further improved as compared with the composition composed of the starch and the thermoplastic synthetic resin. In a composition containing a starch, a thermoplastic synthetic resin, a modifying component, paper powder, and an inorganic substance, the fluidity is further improved as compared to a composition composed of starch and a thermoplastic synthetic resin. And the heat of combustion of the composition can be further reduced.

When waste paper is used as the paper powder and waste material is used as the synthetic resin, resources can be effectively used in an environmental recycling society, and resource saving can be achieved.

Claims (3)

[Claims] 1. A low-combustion heat component mainly composed of starch and a high-combustion heat component mainly composed of a thermoplastic synthetic resin whose combustion heat is higher than that of said starch, and these components are mixed. A molding composition obtained by the above method, wherein the starch has a particle size of 1 to 100 μm, and the composition comprises more than 50% by weight and 70% by weight or less of the low combustion heat component; % By weight and less than 50% by weight of the high combustion heat component, wherein the weight% of the low combustion heat component and the high combustion heat component in the composition is such that the low combustion heat component> the high combustion heat component The above composition, which is in a relationship. 2. The high-combustion heat component is selected from at least one of a thermoplastic elastomer, a hydrogenated styrene-butadiene rubber, a styrene-ethylene butylene / olefin crystal block copolymer, an olefin crystal / ethylene butylene / olefin crystal block copolymer. Contains a formed thermoplastic modifying component, wherein the modifying component is
The composition according to claim 1, wherein the composition accounts for 3% by weight or more and 20% by weight or less of the weight% of the high combustion heat component. 3. A paper powder in which the low combustion heat component has a particle size of 50 μm or more and 200 μm or less, and at least one powdered inorganic substance of titanium oxide, talc, calcium carbonate, calcium sulfate, barium sulfate, and kaolin. And the paper powder accounts for 10% by weight or more and 30% by weight or less of the low-burning heat component by weight, and the inorganic substance accounts for 1% by weight of the low-burning heat component. The weight percentage of the starch, the paper powder, and the inorganic substance is in the relationship of starch> paper powder or inorganic substance, and starch> paper powder + inorganic substance. The composition according to claim 2.