JP2003326556A - Method for manufacturing natural fiber-blended resin molded product such as waste paper, and composition for manufacturing the molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a molded product of a synthetic resin blended with a natural fiber such as waste paper, which draws attention as one method for recycling the waste paper or the measures to reduce a combustion calorie, and eliminates an uncomfortable odor or a gum generated in a mold during thermal molding, and a composition for manufacturing the molded product which is odorless and applied to various uses. <P>SOLUTION: The method for manufacturing a molded product of a resin blended with a natural fiber such as waste paper comprises the steps of melt- kneading a powdered substance of the material fiber such as waste paper and a thermoplastic resin at specified loads to obtain a principal material, then adding a calcium oxide additive containing 0.2 to 5 pts.wt. of calcium oxide to 100 pts.wt. of the principal material and thermally molding the mixture of the principal material and the calcium oxide additive not through undergoing a history of the chemical reaction of the calcium oxide to manufacture the molded product of a resin blended with a natural fiber such as waste paper. In addition, an additive lubricant is added before the thermal molding step. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a natural fiber-containing resin molded article such as waste paper, and a composition for producing the molded article.

In this specification, the term "natural fiber" includes waste paper, hemp, jute (burlap), kenaf (hemp), wood pulp, and waste materials produced during the production of paper products. The term "cotton" also includes cotton-like aggregates of natural fibers.

[0003]

2. Description of the Related Art Conventionally, a substance (powder substance of natural fiber such as waste paper) and at least one of a powdery substance, cotton-like substance and strips of natural fiber such as waste paper and heat of synthetic resin, especially polypropylene etc. The technique of kneading with a plastic resin and using it as a forming raw material has been attracting attention as one method of recycling used paper or as a measure for reducing burned calories. BACKGROUND ART A resin molded product is manufactured from a composite material of a powdered substance of natural fibers such as waste paper and a thermoplastic resin by using, for example, an injection molding die.

[0004]

However, when a resin molded product is manufactured from a composite material of a powdery substance of a natural fiber such as waste paper and a thermoplastic resin as described above, an unpleasant odor (hereinafter , Unpleasant odor) occurs, and so-called “tars” adhere to the injection mold,
There was a problem that the mold was contaminated and the work of removing the "tar" was troublesome.

Therefore, as a result of intensive studies conducted by the present inventors in view of the above points, the cause of the unpleasant odor during heat molding and the generation of "die" in the mold are both natural fibers (cellulose) such as waste paper. It was found to be due to the thermal decomposition (burnt) of.

In particular, the decomposition products consist of acidic substances such as acetic acid, neutral substances such as alcohols, esters or aldehydes, and very small amounts of alkaline substances such as amines. Acidic substances may be produced directly from cellulose, but may also be produced from the thermal oxidation of neutral substances. Here, since the acidic substance also serves as a raw material for ester production, which is one of the causes of die generation in the mold,
The decomposition products accounted for the largest proportion of the acidic substances, and it is considered that these are the main causative substances of the unpleasant odor during heat molding and the generation of mold dies.

Of these decomposition products, those which are volatile are considered to be the causative substances that mainly cause unpleasant odors, and those which are not volatile are considered to be the causative substances that cause mold die generation. .

In particular, it is difficult to apply a natural fiber-containing resin molded product such as waste paper, which has such an unpleasant odor during heat molding, to a product such as daily life goods which does not like the odor, and its use is limited. There was envy.

Other factors may be considered as the cause of the unpleasant odor during heat molding and the generation of mold dies, and it is considered that various factors are overlapped to generate decomposition products.

As a result of intensive studies conducted by the present inventors in view of the above points, as a first method, a kneaded material of a powdered substance of natural fiber such as waste paper and a thermoplastic resin such as polypropylene is used as a molding raw material. When performing injection molding, by mixing a predetermined amount of a calcium oxide-based additive with the kneaded product, an acidic substance that is an odorous component and an acidic substance that is a raw material for ester formation by reaction with calcium oxide in the additive. Can be neutralized to convert a decomposition product of an unpleasant odor and a source of "tar" into another stable neutral substance, and suppress the generation of both unpleasant odor and "tar". As a second method, by adding a specific external lubricant to a kneaded product of a powdery substance of natural fibers such as waste paper and a thermoplastic resin such as polypropylene, thermal decomposition of natural fibers such as waste paper (cellulose) is generated. object By preventing contact with the mold, "tar" that can be suppressed from adhering to the mold, found, thereby completing the present invention.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to give an unpleasant odor and a mold die when heat-molding a kneaded product of a powdered substance of a natural fiber such as waste paper and a thermoplastic resin such as polypropylene. It is an object of the present invention to provide a method for producing a natural fiber-containing resin molded product such as waste paper, which can be eliminated and can be used for various purposes without odor, and a composition for producing the molded product.

[0012]

Means for Solving the Problems and Effects of the Invention In order to achieve the above object, a method for producing a natural fiber-containing resin molded product such as waste paper according to the invention of claim 1 of the present invention is At least one of powder, cotton and strip
30 to 70 parts by weight of a substance composed of two (ie, a powdered substance of natural fiber such as waste paper) and 70 to 30 parts by weight of a thermoplastic resin are melt-kneaded under a temperature condition of the melting point of the thermoplastic resin or more, A melt-kneading step for forming 100 parts by weight of the material,
For 100 parts by weight of this main material, calcium oxide (Ca
O) After the additive mixing step of mixing the calcium oxide-based additive containing 0.2 to 5 parts by weight and the calcium oxide-based additive mixing step, the main material and the calcium oxide are not passed through the history of reaction of calcium oxide. Thermoforming a mixture of system additives,
It is characterized by including a heat molding step of forming a natural fiber-containing resin molded product such as waste paper.

The above-mentioned calcium oxide type additive is a calcium oxide simple substance or a melt-kneaded pellet of calcium oxide and an olefin resin.

Further, in the method for producing a natural fiber-containing resin molded product such as waste paper according to claim 1, the melt-kneading step comprises:
Including a step of pelletizing the main material made of powdered material of natural fibers such as waste paper and thermoplastic resin into a pellet form, the calcium oxide additive mixing step, the pelletized main material,
It is preferable that the melt-kneaded pellets of calcium oxide and olefin resin are tumbled.

In this case, the mixing ratio of calcium oxide of the calcium oxide type additive and the olefin resin is
x: (1-x) (where x is 0.3 to 0.7)
Is preferred.

According to the method for producing a natural fiber-containing resin molded product such as used paper according to the first aspect of the present invention, a kneaded material of a powdered substance of natural fiber such as used paper and a thermoplastic resin such as polypropylene is used as a molding raw material. When performing molding such as injection molding, blow molding, or extrusion molding, since a predetermined amount of calcium oxide-based additive is mixed in the kneaded product, an acidic substance that is an odor component due to reaction with the calcium oxide-based additive It is also possible to neutralize the acidic substance that is the raw material for ester formation and to convert the decomposition product of the unpleasant odor and the source of "dani" into another stable neutral substance. It is possible to suppress the occurrence of both of the above, and it is possible to eliminate the unpleasant odor at the time of heat molding and the occurrence of mold dies.

In the method for producing a natural fiber-containing resin molded product such as used paper according to the present invention, it is preferable that a lubricant addition step of adding an external lubricant is further included before the heat molding step.

In this specification, "external lubricant"
The term "substance" refers to a substance having a function of imparting lubricity and releasability between a natural fiber-containing resin molded product such as waste paper and a metal wall of a mold.

In the step of adding the lubricant, 0.2 parts of the external lubricant is added to 100 parts by weight of the thermoplastic resin in the main material.
~ 3 parts by weight are added.

The external lubricant added in the lubricant addition step is preferably a fatty acid amide. Further, it is preferable that the thermoplastic resin is polypropylene and the fatty acid amide is a saturated fatty acid amide.

Further, the external lubricant added in the lubricant adding step is preferably an acrylic lubricant. Further, it is preferable that the thermoplastic resin is polypropylene and the acrylic lubricant is polymethacrylic acid methyl ester.

In the method for producing a natural fiber-containing resin molded product such as waste paper according to the first aspect of the present invention, the kneaded product of the powdered substance of the natural fiber such as waste paper and the thermoplastic resin such as polypropylene is mixed with a specific external material. By adding a lubricant,
Thermal decomposition of natural fibers (cellulose) such as waste paper can be prevented as much as possible to suppress the generation of decomposition products, and it is possible to eliminate unpleasant odor during heating and mold generation, and to prevent external lubricants from forming. The effect is that the surface of the molded product can be finished smoothly and beautifully.

Next, a composition for producing a natural fiber-containing resin molded product such as used paper according to the invention of claim 11 of the present invention is
30 to 70 parts by weight of a powdered substance of natural fiber such as waste paper and 70 to 30 parts by weight of a thermoplastic resin are melt-kneaded under a temperature condition of a melting point of the thermoplastic resin or more, and pelletized main material 100 formed by pelletizing. Parts by weight and this main material 100
It consists of 0.2 to 5 parts by weight of melt-kneaded pellets of calcium oxide and olefin resin tumbled in parts by weight, and 0.2 to 3 parts by weight of external lubricant with respect to 100 parts by weight of the thermoplastic resin in the main material. It is characterized by that.

According to the composition of the present invention for producing a natural fiber-containing resin molded product such as waste paper according to the invention of claim 11, an acidic substance which is an odor component due to a reaction with a calcium oxide type additive during hot molding. It is also possible to neutralize the acidic substance that is the raw material for ester formation and to convert the decomposition product of the unpleasant odor and the source of "dani" into another stable neutral substance. It is possible to suppress the occurrence of both of the above, and by adding a specific external lubricant, it is possible to prevent the thermal decomposition of natural fibers such as waste paper as much as possible, and suppress the generation of decomposition products. It is possible to eliminate the generation of mold dies and reduce the frequency of work for removing mold dies. In addition, the effect of the external lubricant makes it possible to finish the surface of the molded product smoothly, making it possible to manufacture natural fiber-containing resin molded products such as waste paper that can be used for various purposes such as daily necessities and industrial parts. Produce an effect.

[0025]

Embodiments of the present invention will be described below.

The method for producing a natural fiber-containing resin molded product such as used paper according to the present invention is mainly carried out by melt-kneading a powdered substance of used fiber such as used paper and a thermoplastic resin under a temperature condition higher than the melting point of the thermoplastic resin. A melt-kneading step of forming a material, an additive mixing step of mixing a calcium oxide additive containing a predetermined amount of calcium oxide (CaO) with the main material, and a calcium oxide additive mixing step, and then a calcium oxide A heat molding step of forming a mixture of a main material and a calcium oxide-based additive by heat molding to form a natural fiber-containing resin molded article such as waste paper without undergoing a history of the reaction.

In the above, it is preferable to use polypropylene as the thermoplastic resin, but other polyolefin resins such as polyethylene may be used, and the temperature may be below the temperature at which natural fibers such as waste paper are decomposed, for example, about 300 ° C. Up to, preferably, a thermoplastic resin having a melting point of 260 ° C. or lower.

Further, as the above-mentioned natural fibers such as used paper, usually used paper is used, but it is also possible to use waste materials produced during the production of paper products. In short, powdered materials of natural fiber (cellulose) and cotton. Any materials and strips can be used.

In the melt-kneading step, 30-70 parts by weight, preferably 4 parts by weight of a powdered substance of natural fiber such as waste paper is used.
0 to 60 parts by weight, preferably 45 to 55 parts by weight, and 70 to 30 parts by weight, preferably 60 to 40 parts by weight, preferably 55 to 45 parts by weight of the thermoplastic resin, at a temperature condition not lower than the melting point of the thermoplastic resin. Melt and knead below to form 100 parts by weight of base material.

Here, if 100 parts by weight of the main material contains less than 30 parts by weight of powdered substances of natural fibers such as waste paper and more than 70 parts by weight of thermoplastic resin, powdered substances of recycled fibers such as waste paper. It is not preferable because it has a low effect of improving the high elastic modulus and heat resistance, which are features of a mixture of a resin and a thermoplastic resin, and cannot achieve recycling of waste paper and reduction of calories burned in a resin molded product. Further, when the powdered substance of natural fiber such as waste paper exceeds 70 parts by weight and the thermoplastic resin is less than 30 parts by weight, the MI (melt index) of the kneaded product becomes low and the tensile strength of the molded product also decreases. As such, the physical properties of the resin molded product are impaired, which is not preferable.

Next, in the additive mixing step,
Calcium oxide 0.2 to 5 parts by weight, preferably 0.2 to 3 parts by weight, desirably 0.5 to 100 parts by weight of a main material composed of a powdered substance of natural fibers such as waste paper and a thermoplastic resin.
Calcium oxide based additive including 2.5 parts by weight is mixed.

As described above, when the calcium oxide type additive is mixed with the main material composed of the powdered substance of the natural fiber such as waste paper and the thermoplastic resin, the acidic substance which is the odor component at the time of heat molding is neutralized, Deodorizing effect and strength as molding resin are improved, but MI (melt index)
And the flow of the kneaded product tends to be poor.

That is, if the calcium oxide in the calcium oxide-based additive is less than 0.2 parts by weight with respect to 100 parts by weight of the main material consisting of a powdered substance of natural fibers such as waste paper and a thermoplastic resin, By neutralizing the acidic substance that is an odor component and the acidic substance that is the raw material for ester formation by the reaction with calcium oxide in the additive, the decomposition product of the source of unpleasant odor and "cracker" It is not preferable because it can be converted into a sexual substance and cannot exert the effect of suppressing the generation of both unpleasant odor and "smudge". When the amount of calcium oxide in the calcium oxide-based additive exceeds 5 parts by weight, the action of suppressing the generation of decomposition products that cause unpleasant odor does not change so much, and conversely, the flow of the kneaded product deteriorates, Moldability is significantly reduced, which is not preferable.

In the present invention, after the step of mixing the calcium oxide-based additive, the mixture of the main material and the calcium oxide-based additive is added without a history of reaction of calcium oxide.
For example, it is important to heat-mold at a temperature of 300 ° C. or lower, preferably 260 ° C. or lower to produce a natural fiber-containing resin molded product such as used paper.

In this case, decomposition products are produced during the heat molding for producing a natural fiber-containing resin molded product such as waste paper, which is an acidic substance such as acetic acid, a neutral substance such as alcohol, ester or aldehyde, And a very small amount of an alkaline substance such as amine. Acidic substances, which may be produced directly from cellulose, alcohol,
It can also be generated from the thermal oxidation of neutral substances such as esters or aldehydes. Therefore, the decomposition products account for the largest proportion of acidic substances, and among these acidic substances, those that are volatile are mainly causative substances that generate unpleasant odors, and those that are not volatile are It becomes a raw material for ester formation, which is one of the causes of tar formation.

Here, as the calcium oxide-based additive, calcium oxide (CaO) alone or a melt-kneaded pellet of calcium oxide and an olefin resin is used. Here, as the olefin resin, linear polyethylene, particularly linear low density polyethylene (LLDP) is used.
E), and ultra low density polyethylene (VLDPE), or polypropylene, etc. are used. As an additive, it is better to use melt-kneaded pellets of calcium oxide and an olefin resin than calcium oxide alone, because the dispersibility is good and the reactivity is high, and the water absorption of calcium oxide (CaO) is high. Is suppressed, and the calcium oxide (CaO) powder does not scatter with wind, so
preferable.

The mixing ratio of calcium oxide and olefin resin in the melt-kneaded pellets of the calcium oxide type additive is x: (1-x) (where x is 0.3 to 0.7).

Here, if the proportion of calcium oxide in the calcium oxide type additive is less than 0.3 and the proportion of olefin resin exceeds 0.7, the calcium oxide content in the additive is too small, resulting in decomposition and formation. I can not suppress the generation of things,
In addition, the physical properties of the olefin resin have a considerable influence on the physical properties of the final molded product, which is not preferable. On the other hand, if the proportion of calcium oxide exceeds 0.7 and the proportion of olefin resin is less than 0.3, the dispersibility of the calcium oxide-based additive melt-kneaded pellets in the main material deteriorates,
Not preferable.

In the method of the present invention, the melt-kneading step includes a step of pelletizing a main material composed of a powdered substance of a natural fiber such as waste paper and a thermoplastic resin into pellets. The pelletized main material is obtained by tumbling melt-kneaded pellets of calcium oxide and an olefin resin.

Further, in the method of the present invention, it is preferable to carry out a lubricant addition step of further adding an external lubricant before the heat molding step.

As the external lubricant, it is preferable to use a lubricant made of fatty acid amide, especially saturated fatty acid amide. As the external lubricant, it is preferable to use an acrylic lubricant, especially a lubricant made of polymethacrylic acid methyl ester.

In the step of adding a lubricant, by adding an external lubricant to the main material, MI (melt index) is increased and the flow of the kneaded product is improved, but the strength as a molding resin tends to be lowered.

In the step of adding the lubricant, 0.2 to 3 parts by weight of an external lubricant is added to 100 parts by weight of the thermoplastic resin in the main material, but 100% by weight of the thermoplastic resin in the main material is added to the outside. If the amount of the lubricant is less than 0.2 parts by weight, the action and effect of the external lubricant is low, which is not preferable. Further, if the external lubricant exceeds 3 parts by weight, the physical properties of the molding resin, such as bending strength and heat resistance, are deteriorated, which is not preferable.

Further, in the present invention, the composition for producing a natural fiber-containing resin molded product such as waste paper comprises 30 to 70 parts by weight of a powdered substance of a natural fiber such as waste paper and 70 to 30 parts by weight of a thermoplastic resin. 100 parts by weight of a pellet-shaped main material formed by pelletizing while being melt-kneaded under a temperature condition equal to or higher than the melting point of, and melt-kneaded pellets of calcium oxide and olefin resin tumbled to 100 parts by weight of the main material 0.2 ~ 5 parts by weight and the thermoplastic resin 100 in the main material
It is composed of 0.2 to 3 parts by weight of external lubricant with respect to parts by weight.

In the case of producing a natural fiber-containing resin molded article such as waste paper, a heating step for melting or softening a thermoplastic resin such as polypropylene is carried out during molding such as injection molding, blow molding or extrusion molding. The heating temperature at this time is 300 ° C. or lower, preferably 260 ° C. or lower, and desirably 200 ° C. or lower.

Before or during this heating step, the calcium oxide additive is incorporated into the thermoplastic resin. When the calcium oxide-based additive is mixed before or during the heating step, it is preferable to add it immediately before the final heating step as much as possible. This is because the calcium oxide-based additive can efficiently contribute to deodorization.

The amount of the calcium oxide-based additive to be mixed is
In order to obtain the deodorizing effect, it is preferably 0.2 to 5 parts by weight with respect to 100 parts by weight of the mixture of the thermoplastic resin and the cellulosic powder. In order to keep the pH of the surface of the molded article neutral, the calcium oxide-based additive is used in the mixture 10
It is preferable to mix 2 to 2.5 parts by weight with respect to 0 parts by weight. Further, the particle size of the calcium oxide-based additive to be mixed is preferably small.

[0048]

EXAMPLES Examples of the present invention will be described below.

Examples 1 to 4 A main material consisting of 50 parts by weight of powdered waste paper and 50 parts by weight of polypropylene resin was melt-kneaded under the temperature condition of 190 ° C., which is higher than the melting point of polypropylene resin, and pelletized. Pelletized to. Then, the pelletized main material was tumbled with a calcium oxide-based additive consisting of mixed pellets of calcium oxide and an olefin resin.

Here, as the calcium oxide type additives of Examples 1 to 3, the trade name "master pellet Bell
CML-VE ”(blending ratio; CaO 6.5: ultra-low density polyethylene 3.5, particle size 1 μm, manufactured by Omi Chemical Industry Co., Ltd.) is used as the calcium oxide additive of Example 4 under the trade name“ Master Pellet Bell CML-E
O "(mixing ratio; CaO5.0: linear low-density polyethylene 5.0, particle size 7 to 8 μm, manufactured by Omi Chemical Industry Co., Ltd.)
It was used. The blending ratio of the calcium oxide-based additive to 100 parts by weight of the main material is summarized in Table 1 below.

Then, in Examples 1 to 4, after tumbling of the calcium oxide type additive, the composition for producing a waste paper-containing resin molded product heated to 190 ° C. was injection-molded without undergoing a history of reaction of calcium oxide. The dumbbell-shaped test pieces were manufactured by placing them in a mold of a machine and thermoforming.

Physical properties, that is, tensile strength (JIS K7113) and flexural strength (J
IS K7203) and MI (melt index, JIS K7111; 195 ° C., 21.
6 kg) was measured, and the obtained results are shown in Table 1 below.

In Examples 1 to 4, the mold used was thoroughly washed in advance, and dumbbell-shaped test pieces were molded at 230 ° C., which is a high temperature condition, in order to promote the adhesion of the resin to the mold. However, the generation of resin mold dies due to acidic substances caused by the thermal decomposition of waste paper during heat molding and an unpleasant odor (unpleasant odor)
Occurrence was evaluated, and the obtained results are also shown in Table 1 below.

Examples 5 to 8 Prior to the thermoforming step of Example 1 described above, a lubricant addition step of further adding an external lubricant was carried out. Here, as the external lubricant of Examples 5 and 6, a fatty acid amide lubricant "Brand name Thripax E" (main component: saturated fatty acid amide, manufactured by Nippon Kasei Co., Ltd.) was used, and the external lubricant of Examples 7 and 8 was used. Acrylic lubricant "Brand name Metabrene L-100
0 "(main component: polymethacrylic acid methyl ester, manufactured by Mitsubishi Rayon Co., Ltd.) was used. In addition, the main material 10
The compounding ratio of the external lubricant to 0 part by weight is summarized in Table 1 below.

Then, in Examples 5 to 8, after the external lubricant was added, 1
A composition for producing a resin molded product containing waste paper heated to 90 ° C.,
It was put in a mold of an injection molding machine and heat-molded to manufacture dumbbell-shaped test pieces.

For each of the test pieces of Examples 5 to 8 described above, the physical properties, that is, the tensile strength and bending strength were measured, and M
I was measured and the obtained results are shown in Table 1 below.

In Examples 5 to 8 described above, the mold used was thoroughly washed in advance to form dumbbell-shaped test pieces at 230 ° C., which is a high temperature condition, in order to promote the adhesion of tars to the mold. However, the generation of resin mold dies due to acidic substances caused by the thermal decomposition of waste paper during heat molding and an unpleasant odor (unpleasant odor)
Occurrence was evaluated, and the obtained results are also shown in Table 1 below.

Reference Examples 1 to 4 As a reference, dumbbell-shaped test pieces were prepared in which the main material was not mixed with the calcium oxide-based additive but only the external lubricant was added. That is, a main material composed of 50 parts by weight of powdered waste paper and 50 parts by weight of polypropylene resin was melt-kneaded at a temperature of 190 ° C., which is higher than the melting point of polypropylene resin, and pelletized into pellets. Then, to the pelletized main material, in Reference Examples 1 and 2, a fatty acid amide lubricant (trade name: Thripax E) was added, and in Reference Examples 3 and 4, an acrylic lubricant (trade name: METABLEN L-100).
0) was added. The mixing ratio of the external lubricant to 100 parts by weight of the main material is shown in Table 1 below.

Then, in Reference Examples 1 to 4, 190 ° C.
The composition for producing a resin-molded article containing waste paper heated to 1 was placed in a mold of an injection molding machine and heat-molded to produce dumbbell-shaped test pieces.

For each of the test pieces of Reference Examples 1 to 4 described above, the physical properties, that is, the tensile strength and bending strength were measured, and M
I was measured and the obtained results are shown in Table 1 below.

Further, in the above-mentioned Reference Examples 1 to 4, the mold used was thoroughly washed in advance, and a dumbbell-shaped test piece was molded at 230 ° C., which is a high temperature condition, in order to promote adhesion of the resin to the mold. However, the generation of resin mold dies due to acidic substances caused by the thermal decomposition of waste paper during heat molding and an unpleasant odor (unpleasant odor)
Occurrence was evaluated, and the obtained results are also shown in Table 1 below.

Comparative Example For comparison, a dumbbell-shaped test piece is produced from a resin composition containing only the main material without mixing the main material with the calcium oxide type additive and the external lubricant. That is, powdered material 50 of waste paper
A main material composed of 50 parts by weight of polypropylene resin and 50 parts by weight of polypropylene resin was melt-kneaded under the temperature condition of 190 ° C. which is higher than the melting point of polypropylene resin, and pelletized into pellets. Then, the composition for producing a waste paper-containing resin molded product obtained by heating the pelletized main material to 190 ° C. was put into a mold of an injection molding machine and heat-molded to manufacture a blank dumbbell-shaped test piece.

Then, the physical properties of the test piece, that is, the tensile strength and the bending strength were measured, and the MI was measured. In addition, the mold used is sufficiently washed in advance so that the adhesion of the varnish to the mold is promoted.
Molded dumbbell-shaped test pieces at ℃, evaluated the generation of mold dies caused by acidic substances due to thermal decomposition of waste paper during heat molding and the generation of unpleasant odors (unpleasant odors), and obtained the results, It is also shown in Table 1 below.

Here, the generation of mold dies was evaluated at the following stages on the basis of the generation of mold dies at the time of manufacturing a blank test piece.

Generation of die blemishes ◎: Very few die dies (70 to 80% less stain) ◯: Little die dies (60% less stain) △: Mold deficiency in the mold is slightly improved ×: Mold deficiency in the mold remains the same as before, no CaO-based additive and external lubricant are added, and the generation of unpleasant odor during heating is a blank. The odor generated during the production of the test piece was used as a standard for evaluation in the following stages.

Generation of unpleasant odor ◎: Almost no odor (state in which it is difficult to determine whether there is odor) ○: Very little odor (can be identified when there is some odor) Δ: Slight odor Decreased (it can be discerned that there is some odor) ×: There is a odor due to charring of used paper, no CaO-based additive and lubricant added

[Table 1]

As is clear from the results in Table 1 above, in Examples 1 to 4 in which the calcium oxide-based additive was mixed with the main material consisting of the waste paper powder and the polypropylene resin, the calcium oxide-based additive The higher the blending amount, the less the occurrence of mold dies. However, calcium oxide-based additive (brand name Master Pellet Bell CML
1. -VE) is added in an amount of 1.0 parts by weight in Example 2 and 2.
There is no significant difference with 0 parts by weight of Example 3. In addition, the physical properties of the molded product, that is, the tensile strength and the bending strength, are considerably improved, but the MI of the molded product is lowered,
There is a tendency that the flow of the resin composition containing waste paper slightly deteriorates and the moldability deteriorates.

Further, in Examples 5 to 8 in which the calcium oxide type additive and the external lubricant were mixed with the main material composed of the powdery material of waste paper and the polypropylene resin, the generation of tar in the mold and the generation of unpleasant odor occurred. Also few. Therefore, in the maintenance at the time of injection molding, it is possible to reduce the frequency of the work of removing the mold varnish, and it is possible to manufacture a waste paper-containing resin molded product that has no odor and can be used for various purposes. Moreover, by mixing the external lubricant, the surface of the molded product became smooth and the surface property was good. In addition, the physical properties of the molded product, that is, the tensile strength and bending strength, are slightly improved.

It should be noted that Reference Examples 1 to 1 in which only an external lubricant is mixed with a main material made of a powdery material of waste paper and a polypropylene resin
In No. 4, the generation of mold dies was reduced, but the generation of unpleasant odor was recognized. Further, although the surface property was good, the physical properties of the molded product, that is, the tensile strength and bending strength were deteriorated. However, the MI of the molded product did not decrease so much, the flow of the resin composition containing waste paper was good, and the moldability was excellent.

As can be seen from the results in Table 1 above, the calcium oxide type additive and the external lubricant have mutually contradictory effects, and the former compounding causes the generation of mold dies and the generation of unpleasant odor. And the physical properties are improved, but the moldability is lowered. On the other hand, the latter formulation can prevent the generation of mold blemishes to some extent, but has almost no effect in preventing the generation of unpleasant odors, and the physical properties of the molded product are also reduced. However, the formability is increased. Therefore, by using both in combination, the effect of preventing the generation of tars and unpleasant odors in the mold is sufficiently observed, and the MI lowered by the addition of CaO is improved by the addition of the external lubricant, and the addition of the external lubricant is added. The strength decreased by CaO
Can be improved by the addition of.

In the above embodiment, the method for producing a natural fiber-containing resin molded product such as waste paper and the composition for producing the molded product according to the present invention are applied to injection molding to prevent generation of mold blister and discomfort. I explained the effect of preventing the generation of odor,
The production method and the composition of the present invention include, in addition, a metal die used for extrusion molding and blow molding, a melt-kneaded product of a powdered substance of a natural fiber such as waste paper and a composite material of a thermoplastic resin, and a metal die. It can be applied to any of the methods for producing a resin molded product by direct contact.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 23/10 C08L 23/10 33/10 33/10 101/00 101/00 // B29K 23:00 B29K 23:00 105: 16 105: 16 F term (reference) 4F071 AA08 AA20 AA33 AB18 AC09 AE11 AF03 AH19 BA01 BB05 BC07 4F206 AA11 AA50 AB07 AB16 AB19 AC04 AM32 JA07 JE30 JF02 JF06 JF22 4J002 AB01W BB05X 176 FD086 EN07

Claims (11)

[Claims] 1. A substance comprising at least one of a powdery material, a cotton-like material and a strip of a natural fiber such as waste paper (hereinafter referred to as a powdery substance of a natural fiber such as waste paper) 30 to 70 parts by weight,
And a melt-kneading step of forming 70 to 30 parts by weight of the thermoplastic resin under a temperature condition equal to or higher than the melting point of the thermoplastic resin to form 100 parts by weight of the main material, and oxidizing 100 parts by weight of the main material. After the additive mixing step of mixing a calcium oxide-based additive containing 0.2 to 5 parts by weight of calcium and the calcium oxide-based additive mixing step, the main material and the calcium oxide-based additive are not passed through the history of reaction of calcium oxide. A method of producing a natural fiber-containing resin molded product such as waste paper, which comprises a heat molding step of forming a mixture of additives by heat molding to form a natural fiber-containing resin molded product such as waste paper. 2. The method for producing a natural fiber-containing resin molded product such as waste paper according to claim 1, wherein the calcium oxide-based additive is calcium oxide alone or a melt-kneaded pellet of calcium oxide and an olefin resin. 3. The melt-kneading step includes a step of pelletizing a main material made of a powdered substance of a natural fiber such as waste paper and a thermoplastic resin into pellets, and the calcium oxide-based additive mixing step is pelletized. The method for producing a natural fiber-containing resin molded product such as used paper according to claim 1, wherein melt-kneaded pellets of calcium oxide and an olefin resin are tumbled. 4. The compounding ratio of calcium oxide of the calcium oxide-based additive and the olefin resin is x: (1-x) (where, x is 0.3 to 0.7). 3. A method for producing a natural fiber-containing resin molded product such as waste paper according to 3. 5. The method for producing a natural fiber-containing resin molded product such as waste paper according to claim 1, further comprising a lubricant addition step of adding an external lubricant before the heat molding step. 6. The natural fiber-containing resin molded product such as waste paper according to claim 5, wherein 0.2 to 3 parts by weight of an external lubricant is added to 100 parts by weight of the thermoplastic resin in the main material in the lubricant adding step. Production method. 7. The method for producing a natural fiber-containing resin molded product such as used paper according to claim 5, wherein the external lubricant added in the lubricant addition step is a fatty acid amide. 8. The thermoplastic resin is polypropylene,
8. The fatty acid amide is a saturated fatty acid amide.
A method for producing a natural fiber-containing resin molded product such as the described waste paper. 9. The method for producing a natural fiber-containing resin molded product such as waste paper according to claim 5, wherein the external lubricant added in the lubricant adding step is an acrylic lubricant. 10. The method for producing a natural fiber-containing resin molded article such as waste paper according to claim 9, wherein the thermoplastic resin is polypropylene and the acrylic lubricant is polymethacrylic acid methyl ester. 11. A powdery substance 30-70 of natural fiber such as waste paper.
100 parts by weight of a pellet-shaped main material formed by pelletizing and forming 100 parts by weight of the thermoplastic resin and melt-kneading 70 to 30 parts by weight of the thermoplastic resin under a temperature condition equal to or higher than the melting point of the thermoplastic resin. Melt-kneaded pellets of tumbled calcium oxide and olefin resin 0.2 to
A composition for producing a natural fiber-containing resin molded product such as waste paper, which comprises 5 parts by weight and 0.2 to 3 parts by weight of an external lubricant with respect to 100 parts by weight of the thermoplastic resin in the main material. .