JP2011173948A - Method for regenerating glass fiber-reinforced polypropylene material and regenerated molded article of glass fiber-reinforced polypropylene material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inhibit discoloration when a regenerated molded article is molded from a molded article of a glass fiber-reinforced polypropylene material (FR-PP material), and to produce a good regenerated molded article. <P>SOLUTION: When a molded article of an FR-PP material is pulverized and this pulverized material is used as a raw material to mold a regenerated molded article, a thioether-based antioxidant is added when the pulverized material is melted by heating and pelletized, or a thioether-based antioxidant is added when the pulverized material is injection molded as it is. Cases (embodiments 1 to 3) of using the thioether-based antioxidant as an antioxidant in recycling can reduce yellowing degree as compared with cases (comparative examples 1 and 2) using no antioxidant and cases (comparative examples 3 to 5) using a phenolic antioxidant. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for regenerating a glass fiber reinforced polypropylene material when a molded product of a glass fiber reinforced polypropylene material is pulverized and a regenerated molded product is formed using the pulverized material as a raw material, and a glass fiber reinforced polypropylene produced by the method. Recycled molded products.

  In recent years, the Home Appliance Recycling Law (Specific Household Equipment Re-Production Law) has been enacted, and efforts are being made to reuse recycled materials for home appliances, especially polypropylene materials that are used in large quantities in washing machines and the like. Among these, recent washing machines are often provided with a drying function. For this reason, in order to maintain rigidity even under high temperature conditions, a glass material in which about 10 to 25 wt% glass fiber is mixed in a polypropylene material. The frequency of using a fiber reinforced polypropylene material (hereinafter referred to as FR-PP) is increasing. For this reason, in order to maintain a recycling rate above a certain level, it is necessary to recycle the FR-PP material.

JP 2001-329178 A JP 2006-335980 A

  In general, additives (maleic acid-modified polypropylene and urethane-based additives) for increasing the adhesion between glass fiber and polypropylene material are added to the FR-PP material. When such a FR-PP material is recycled to form a regenerated molded product, there is a problem that the brown color is caused by heat during molding. In addition, the strength decreases greatly, and cannot be used as it is. For this reason, the recycling rate in home appliance recycling is reduced, and these materials can only be used by being discarded, landfilled, or burned as fuel, resulting in a high environmental load.

In addition, about the point which adds antioxidant to FR-PP material, it is disclosed by patent document 1, 2, for example.
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to produce a good recycled molded product that can suppress discoloration when molding a recycled molded product from a molded product of FR-PP material. It is an object of the present invention to provide a method for regenerating a glass fiber reinforced polypropylene material and a regenerated molded product.

  As a method of mixing glass fiber with polypropylene when producing a molded product of FR-PP material, generally, when molding using pellets premixed with glass fiber (in this case, general Glass fiber becomes short fiber) and when masterbatch made by coating polypropylene on glass fiber long fiber and cutting with a pelletizer is mixed with polypropylene material without glass fiber and molded ( In this case, it is generally a long fiber). At this time, in order to increase the adhesion between the glass fiber and the polypropylene, a glass fiber silicone coupling agent is added, and maleic acid-modified polypropylene and a urethane-based additive (isocyanate compound) are further mixed.

  In general, as an antioxidant for polypropylene, a phenolic antioxidant that is the cheapest and most effective is often added. Since this antioxidant is consumed by the heat history, if it is recycled as it is, the long-term heat resistance tends to be lower than when it is molded with a virgin agent. Therefore, when the FR-PP material is recycled, long-term heat resistance can be improved by adding this consumed and insufficient phenolic antioxidant. However, when recycled in this way, there has been a problem that the regenerated molded product will turn brown.

Accordingly, as a result of intensive studies to solve the above problems, the present inventors have found the cause of discoloration. That is, when recycling the FR-PP material, heat is added to the phenolic antioxidant and the maleic acid-modified polypropylene or urethane-based additive, and when they react, they are colored via an amide bond. The substance was produced and turned brownish brown.
Then, the present inventors have found that it is effective to use a thioether-based antioxidant as an antioxidant that is additionally added when recycling the FR-PP material in order to suppress the above discoloration, and the present invention. I found.

The invention of claim 1 is a method for regenerating a glass fiber reinforced polypropylene material when a molded product of a glass fiber reinforced polypropylene material (FR-PP material) is pulverized and a regenerated molded product is formed using the pulverized material as a raw material. A thioether antioxidant is added when the pulverized material is heated and melted to be pelletized.
According to this method, when a pulverized material of FR-PP material is heated and melted to be pelletized, a thioether-based antioxidant is added, and the recycled molded product is molded using the pellet. Discoloration can be suppressed, and a good recycled molded product can be produced.

As another method of adding a thioether antioxidant, there is a method of adding a thioether antioxidant when injection molding is performed by an injection molding machine using a pulverized material obtained by pulverizing a molded product of FR-PP material ( Invention of Claim 2).
Further, as another method of adding a thioether-based antioxidant, pellets added with a thioether-based antioxidant when molded by an injection molding machine using a pulverized material obtained by pulverizing a molded product of FR-PP material There is a method of mixing materials (invention of claim 3).
In the inventions of the second and third aspects, the same effect as that of the first aspect can be obtained.

In the first to third aspects of the invention, the amount of thioether-based antioxidant added is preferably 0.1 to 0.5 wt% (the fourth aspect of the invention).
As a result of experiments on the relationship between the addition amount of thioether antioxidant and the yellowing degree, the yellowing degree decreases as the addition amount of thioether antioxidant increases to 0.3 wt%. Even if it becomes above, yellowing degree hardly changes, and when the addition amount is 0.5 wt% or more, the color of the additive itself causes discoloration, the cost increases, and the merit of using recycled materials decreases. The shortcoming comes out. Further, when the addition amount is 0.1 wt% or less, the discoloration suppressing effect is low. For this reason, it is preferable to set it as 0.1-0.5 wt% as addition amount of the thioether type antioxidant in the case of recycling, More preferably, it is around 0.3 wt%.

  The invention of claim 5 is a recycled molded product of polypropylene material molded by the method of claim 1. The invention of claim 6 is a recycled molded product of polypropylene material molded by the method of claim 2. A seventh aspect of the present invention is a recycled molded product of a polypropylene material molded by the method of the third aspect. The invention of claim 8 is characterized in that, in the inventions of claims 5 to 7, the addition amount of the thioether antioxidant is 0.1 to 0.5 wt%.

  As antioxidants for polypropylene materials, there are phosphoric acid antioxidants in addition to the above-mentioned phenolic antioxidants and thioether antioxidants. Phosphorous antioxidants are excellent in antioxidant ability at the time of thermoforming and are often used as processing stabilizers. This phosphate-based antioxidant is used as a processing stabilizer because of its high reactivity to remove peroxides, and is suitable for preventing oxidation due to heating during injection molding. It is easy to react with the maleic acid-modified polypropylene and isocyanate to cause yellowing.

Therefore, in the invention of claim 9, in the method for regenerating a glass fiber reinforced polypropylene material according to claim 1, when the pulverized material is melted by heating and pelletized, 0.2 wt% of the phosphoric acid antioxidant is added. The following is added.
In the invention of claim 9, in addition to the thioether-based antioxidant, the addition of a phosphoric acid-based antioxidant can further suppress discoloration of the regenerated molded product of the FR-PP material, and a better regenerated molded product can be obtained. It can be manufactured. In addition, it is easy to cause yellowing when the addition amount of the phosphoric acid antioxidant exceeds 0.2 wt%.

  As another method of adding a phosphoric acid-based antioxidant, a phosphoric acid-based oxidation method in the method for regenerating a glass fiber reinforced polypropylene material according to claim 2, wherein the pulverized material is used for injection molding by an injection molding machine. There is a method of adding an inhibitor (invention of claim 10). Also by such a method, the same effect as that of the ninth aspect of the invention can be obtained.

  The invention of claim 11 is a recycled molded product of a polypropylene material molded by the method of claim 9. A twelfth aspect of the present invention is a recycled molded product of polypropylene material molded by the method of the tenth aspect.

  ADVANTAGE OF THE INVENTION According to this invention, discoloration of the reproduction | regeneration molding product of FR-PP material can be suppressed, and it becomes possible to manufacture a favorable reproduction | regeneration molding product.

The figure which shows the measurement result of yellowing degree Characteristic diagram showing the relationship between the amount of thioether antioxidant added and the degree of yellowing Characteristic chart showing the relationship between the amount of phosphate antioxidant added and the degree of yellowing

(First embodiment)
In order to confirm the effect of the present invention, the following examples and comparative examples were performed.
First, Embodiments 1 to 3 of the present invention will be described with reference to FIG.
As raw materials for manufacturing recycled molded products of FR-PP material, FR-PP material molded products collected from the market (hereinafter referred to as market-collected products) and mill materials (industrial waste at the factory) Runners and the like) and defective moldings (hereinafter referred to as factory waste) were prepared, and these raw materials were finely pulverized by a pulverizer.

  In Example 1, the market-collected product was used as a raw material, and the pulverized material obtained by pulverizing the market-collected product was directly put into an injection molding machine, and a powdery thioether-based antioxidant was added to make them uniform. Mixed. Note that the pulverized material and the thioether-based antioxidant may be mixed in advance before being put into the injection molding machine, and may be put into the injection molding machine in a mixed state. At this time, the addition amount of the thioether antioxidant was 0.3 wt%. The pulverized material charged into the injection molding machine is heated and melted in the injection molding machine. A regenerated molded product was obtained by injection molding with this injection molding machine.

  In Example 2, a market-recovered product was used as a raw material, and a pulverized material obtained by pulverizing the market-recovered product was once pelletized by a rudder. When pelletizing, a thioether antioxidant was added and mixed. The pulverized material is once heated and melted when pelletized. At this time, the amount of the thioether-based antioxidant added was also 0.3 wt%. Then, the pellets thus produced were put into an injection molding machine and injection molded to obtain a regenerated molded product.

  In Example 3, the factory waste was used as a raw material, and the pulverized material obtained by pulverizing the factory waste was once pelletized by a ruder. When pelletizing, a thioether antioxidant was added and mixed in the same manner as in Example 2. At this time, the amount of the thioether-based antioxidant added was also 0.3 wt%. Then, the pellets were put into an injection molding machine and injection molded to obtain a regenerated molded product.

Next, Comparative Examples 1 to 5 will be described.
In Comparative Example 1, a market-recovered product was used as a raw material, and a pulverized material obtained by pulverizing the market-recovered product was directly put into an injection molding machine and injection molded to obtain a regenerated molded product. In this case, no antioxidant is added.
In Comparative Example 2, factory industrial waste was used as a raw material, and the pulverized material obtained by pulverizing the factory industrial waste was once pelletized by a rudder, and the pellet was put into an injection molding machine and injection molded to obtain a regenerated molded product. Again, no antioxidant is added.

Comparative Example 3 is the same as Example 1 except that the antioxidant to be added is a phenol-based antioxidant and the amount added is 0.2%.
In Comparative Example 4 as well, the antioxidant to be added is a phenolic antioxidant, and the amount added is 0.2%, and the rest is the same as in Example 2.
In Comparative Example 5 as well, the antioxidant to be added is a phenolic antioxidant, the amount of addition is 0.2%, and the rest is the same as Example 3.
Here, the thioether antioxidant used in Examples 1 to 3 of this time is CAS number: 123-28-4, chemical name: 3,3′-thiodipropionate didodecyl, and the structural formula thereof is shown below. (1) and (2). The antioxidant mechanism is shown in the following chemical reaction formula (3).

The sulfur-based antioxidant decomposes R—O—O—H, which is a peroxide generated in the plastic, as shown in this chemical reaction formula (3) (wherein R represents an alkyl group). ). However, the decomposition rate in this case is not so fast, so there is little reaction due to the peroxide generated due to the heat during molding. For this reason, it reacts with maleic acid-modified polypropylene and urethane compounds to cause discoloration (yellowing) Can be prevented.
In addition to the above-mentioned thioether antioxidants, for example, alkyl (C8-18) thiopropionate such as distearyl thiodipropionate, dimyristyl thiopropionate, ditridecyl thiopropionate, etc. Is mentioned.
In FIG. 1, the result of having measured the yellowing degree of the sample of Examples 1-3 and the sample of Comparative Examples 1-5 is shown. The yellowing degree is a value calculated from the chromaticity Lab, and the higher the value, the more yellowish.

Considering FIG. 1, the following can be understood.
First, in the case of Comparative Example 1 in which no antioxidant was added at the time of recycling, a market-recovered product was used as a raw material, and a pulverized material obtained by pulverizing the raw material was directly injection-molded with an injection molding machine. .61. Similarly, in the case of Comparative Example 2 to which no antioxidant was added, the factory waste was used as a raw material, and the pulverized material obtained by pulverizing it was pelletized and injection molded by an injection molding machine. .55. In these Comparative Examples 1 and 2, the degree of yellowing is high.

  On the other hand, in the case of Comparative Example 3, a market-recovered product is used as a raw material, and a phenol-based antioxidant is added when injection molding is performed using a pulverized material. The yellowing in this case The degree is 0.53, which is lower than that of Comparative Example 1. Further, in the case of Comparative Example 4, a phenolic antioxidant was added when pelletizing the pulverized material of the market-recovered product, and the pellet was used for injection molding. 59, which is lower than that of Comparative Example 1. Moreover, in the case of the comparative example 5, the factory production waste is used as a raw material, and when the pulverized material obtained by pulverizing it is pelletized, a phenolic antioxidant is added, and injection molding is performed using the pellet. Is 0.48. In these Comparative Examples 3 to 5, although the yellowing degree is improved as compared with the case where no antioxidant is added (Comparative Examples 1 and 2), the degree is still insufficient, and the addition ratio of the antioxidant However, there was also a drawback that the reaction proceeded more and the degree of yellowing increased.

Here, the reason why the market-collected product has a higher degree of yellowing than the factory waste as raw materials includes ultraviolet stress in the market and deterioration due to oxidation due to long-term use.
On the other hand, in the case of Example 1, which is an example of the present invention, a market-recovered product is used as a raw material, and a thioether-based antioxidant is added when injection molding is performed using a pulverized material obtained by pulverizing it. The yellowing degree in this case is 0.35, which is suppressed more than Comparative Examples 1 and 3. In the case of Example 2, a thioether-based antioxidant was added when pelletizing the pulverized material collected from the market, and injection molding was performed using the resulting pellet. In this case, the degree of yellowing Is 0.42 and is suppressed as compared with Comparative Example 4. Further, in the case of Example 3, the factory waste was used as a raw material, and a thioether-based antioxidant was added when pelletizing the pulverized material, and injection molding was performed using the resulting pellet. The degree of yellowing is 0.31, which is lower than that of Comparative Example 5. From these results, it can be seen that in Examples 1 to 3 to which a thioether-based antioxidant was added, the degree of yellowing was suppressed as compared with Comparative Examples 1 to 5.

  As another method of adding a thioether antioxidant, instead of directly adding a thioether antioxidant when pulverizing a market-recovered product or industrial waste and injection molding using the pulverized material, thioether It is also possible to mix pellets (masterbatch) containing a system antioxidant. In such a case, there is an advantage that the dispersibility of the antioxidant to be added becomes high, and the effect (suppression of yellowing) can be increased with a smaller addition amount.

  FIG. 2 shows the results of measuring the addition amount of the thioether antioxidant and the change in the yellowing degree in order to obtain the optimum addition amount of the thioether antioxidant. The following can be seen from FIG. That is, when the addition amount of the thioether-based antioxidant is up to 0.3 wt%, the yellowing degree gradually decreases as the addition amount increases, but the yellowing degree hardly changes even if the addition amount exceeds that. . When the addition amount exceeds 0.5 wt%, the color changes depending on the color of the additive (thioether antioxidant) itself. Further, when the added amount increases, the cost increases, and there is a disadvantage that the merit of using the recycled material is reduced. From these results, the addition amount of the thioether-based antioxidant when recycling the FR-PP material is preferably 0.1 to 0.5 wt%, more preferably around 0.3 wt%.

(Second Embodiment)
Antioxidants include phosphoric antioxidants in addition to the phenolic antioxidants and thioether antioxidants described so far. Examples of the phosphoric acid antioxidant include tris (2,4-di-tert-butylphenyl) phosphate. Its structural formula is shown in (4) below. Other examples include tris [2-[[2,4,8,10-tetrakis (1,1-dimethylethyl) dibenzo [d, f] [1,3,2] dioxaphosphine-6- Yl] oxy] ethyl] amine. Its structural formula is shown in (5) below.

  Phosphorous antioxidants are excellent in antioxidant ability during thermoforming and are often used as processing stabilizers. The reaction mechanism for removing the peroxide is shown in chemical reaction formula (6). Because of the high reactivity of this phosphate-based antioxidant, it is used as a processing stabilizer and is suitable for preventing oxidation due to heating during injection molding. It easily reacts with modified polypropylene and isocyanate, and easily causes yellowing.

  Therefore, in the present embodiment, as an antioxidant to be added when producing a recycled molded product of FR-PP material, in addition to the thioether-based antioxidant, a phosphorus-based antioxidant is 0.2 wt% or less ( (More than 0). Specifically, as raw materials, the above-mentioned market-recovered FR-PP materials and industrial wastes are pulverized, and when the pulverized material is used as it is for injection molding with an injection molding machine, a thioether-based antioxidant and a phosphorus-based oxidation are used. A regenerated molded product was obtained by injection molding with the addition of an inhibitor. Thus, when manufacturing the regenerated molded product of the FR-PP material, in addition to the thioether-based antioxidant, 0.2 wt% or less of the phosphorus-based antioxidant is added to further reduce the yellowing of the regenerated molded product. It became possible to suppress.

  FIG. 3 shows the results of measuring the amount of addition of the phosphoric acid antioxidant and the change in the degree of yellowing in order to obtain the optimum amount of phosphoric acid antioxidant. FIG. 3 is based on the addition of 3 wt% thioether antioxidant. FIG. 3 shows that the addition amount of the phosphoric acid antioxidant is preferably 0.2 wt% or less. If the added amount exceeds 0.2 wt%, the yellowing degree increases and the reverse effect is obtained.

  As a method for producing a regenerated molded product by adding a phosphoric acid-based antioxidant, the pulverized material obtained by pulverizing the market-collected product and factory waste is re-pelletized by a ruder as a method different from the method described above. In this case, in addition to the thioether-based antioxidant, a phosphoric acid-based antioxidant may be added, and injection molding may be performed using pellets formed thereby. In this case, the addition amount of the phosphoric acid antioxidant is also 0.2 wt% or less. Even if it does in this way, the effect similar to the above-mentioned can be acquired.

  When injection molding is performed using the pulverized material as it is, the heat history is reduced once compared with the case of pelletizing again, so that yellowing can be suppressed and the cost can be reduced. The dispersibility of the agent is worse than when pelletized again, and there is a drawback that the efficiency with respect to the added amount of the antioxidant is deteriorated.

  Examples of phosphoric acid antioxidants include bis [2,4-bis (1,1-dimethylethyl) -6-methylphenyl] ethyl ester phosphorous acid, tetrakis (2,4-di-tert), in addition to those described above. -Ptylphenyl) (1,1-biphenyl) -4,4'-diylbisphosphonite, trinonylphenyl phosphate, triphenyl phosphate and the like.

Claims (12)

  In a method for regenerating a glass fiber reinforced polypropylene material when a molded product of a glass fiber reinforced polypropylene material is pulverized and a regenerated molded product is formed using the pulverized material as a raw material, the thioether is used when the pulverized material is heated and melted to be pelletized. A method for regenerating a glass fiber reinforced polypropylene material, comprising adding a system antioxidant.   In a method for regenerating a glass fiber reinforced polypropylene material when a molded product of a glass fiber reinforced polypropylene material is pulverized and a recycled molded product is formed using the pulverized material as a raw material, a thioether-based oxidation is performed when injection molding is performed using the pulverized material. A method for regenerating a glass fiber reinforced polypropylene material, comprising adding an inhibitor.   In a method for regenerating a glass fiber reinforced polypropylene material when a molded product of a glass fiber reinforced polypropylene material is pulverized and a regenerated molded product is formed using the pulverized material as a raw material, a thioether type is used for injection molding using the pulverized material. A method for regenerating a glass fiber reinforced polypropylene material, comprising mixing a pellet material to which an antioxidant is added.   The method for regenerating a glass fiber reinforced polypropylene material according to any one of claims 1 to 3, wherein the addition amount of the thioether-based antioxidant is 0.1 to 0.5 wt%.   When a molded product of glass fiber reinforced polypropylene material is pulverized, and the recycled product of glass fiber reinforced polypropylene material molded using the pulverized material as a raw material, the pulverized material is melted by heating and pelletized. Recycled molded product of glass fiber reinforced polypropylene material characterized by the addition of   A glass fiber reinforced polypropylene material molded product is pulverized, and a glass fiber reinforced polypropylene material molded from this pulverized material is added to the recycled molded product when injection molding is performed using the pulverized material. Recycled molded product of glass fiber reinforced polypropylene material.   When a molded product of a glass fiber reinforced polypropylene material is pulverized, and a regenerated molded product of the glass fiber reinforced polypropylene material formed from the pulverized material as a raw material, a thioether antioxidant is added during injection molding using the pulverized material. Recycled molded product of glass fiber reinforced polypropylene material, characterized by mixing added pellet materials.   The regenerated molded product of glass fiber reinforced polypropylene material according to any one of claims 5 to 7, wherein the addition amount of the thioether-based antioxidant is 0.1 to 0.5 wt%.   The method for regenerating a glass fiber reinforced polypropylene material according to claim 1, wherein 0.2 wt% or less of a phosphoric acid antioxidant is added when the pulverized material is melted by heating and pelletized.   The method for regenerating a glass fiber reinforced polypropylene material according to claim 2, wherein 0.2 wt% or less of a phosphoric acid antioxidant is added when injection molding is performed using the pulverized material.   The regenerated molded product of glass fiber reinforced polypropylene material according to claim 5, wherein 0.2 wt% or less of a phosphoric acid-based antioxidant is added when the pulverized material is melted by heating and pelletized.   The regenerated molded product of glass fiber reinforced polypropylene material according to claim 6, wherein a phosphoric acid antioxidant is added in an amount of 0.2 wt% or less during injection molding using the pulverized material.

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