JP2008174629A - Molding material and molded part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that, though fibrous reinforcing material such as a glass fiber is generally added in order to enhance mechanical properties of the molding material using a thermosetting resin, lowered flowability of the molding material causes deterioration of productivity and defective molding. <P>SOLUTION: The molding material is made to comprise a thermosetting resin comprised of at least an unsaturated polyester and a crosslinkable monomer, and a fiber derived from a plant. Thus, strengths are enhanced while suppressing lowering of flowability of the molding material. The molding material is easily decomposable by an immersion treatment in an alkaline aqueous solution or the like. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a mold material and a molded part using the mold material.

  Conventionally, when using unsaturated polyester resin or phenol resin, which are thermosetting resins, as a molding material, inorganic fillers such as calcium carbonate and aluminum hydroxide and reinforcing materials such as glass fiber are added to increase the amount and stabilize the dimensions. In general, it has been attempted to reduce the size, prevent shrinkage, improve the strength, prevent sink / warp, flame retardancy, and reduce costs.

As an unsaturated polyester resin BMC (bulk molding compound), for example, Patent Document 1 discloses a method of obtaining a high-strength BMC molded body by adding glass fibers using a sizing agent. Further, Patent Document 2 discloses a molding material that has high strength and can improve the appearance, particularly the weld line, by using a BMC to which inorganic fibers and organic fibers having adjusted lengths are added.
JP-A-5-293823 JP 2001-261924 A

  However, adding glass fiber as a reinforcing material is a very effective method for improving the strength, but tends to reduce the fluidity of the BMC before curing. Therefore, frequent molding defects due to lower fluidity and molding itself may be difficult, and it is necessary to determine the addition amount, shape, type, etc. of glass fiber in consideration of the balance between improved compact strength and lower fluidity. was there. For this reason, it is conceivable that sufficient strength cannot be obtained, or that molding takes a long time and productivity is lowered. Moreover, glass fiber is not familiar with the resin, and it is often necessary to subject the glass fiber to a surface treatment. Furthermore, since glass fiber is easy to pierce the skin and has an adverse effect when sucked, there is a problem in terms of work safety.

  Thermosetting resins, on the other hand, have a complex cross-linked three-dimensional structure due to the curing reaction, so they are generally insoluble and infusible resins, and therefore are difficult to decompose and recycle, and are difficult to reuse. However, recently, as the problem of waste has been raised, various products (buildings, automobiles, electrical products, etc.) have been required to be reused.

  However, unlike the case of metal, the regeneration / reuse of the resin is not technically established, and in particular, it is difficult to regenerate / reuse the molded product. Such a molded product is often used as a structural material. For example, it is often used as a molding material of a mold motor or a semiconductor sealing material. It is also difficult to recycle and reuse various parts and materials. In addition, recycling methods such as FRP (fiber reinforced polymerizable unsaturated monomer-containing thermosetting resin) and its materials, SMC, BMC, etc., such as grinding method, thermal decomposition method, microwave decomposition method, etc. are dedicated. A large-scale device is required, and a large amount of energy may be consumed.

Furthermore, from the viewpoint of protecting the global environment, there is a shortage of waste disposal sites, and there is a need to reuse and recycle vegetable waste.
For example, there is a strong demand for the development of recycling technology for wood waste generated from bark, thinned wood, pruned branches, construction waste, and the like. Since wood-based waste materials are also produced in large quantities, such as palm coconut shell waste, waste leaves, and waste stems that are cultivated in Southeast Asia, development of a method for using them is also desired. Utilization of plant-derived fibrous substances contained in these waste materials will become even more important in the future.

  In view of the above problems, the object of the present invention is to use fibers extracted from plant wastes as a substitute for BMC reinforcing agents, particularly glass fibers, so that it has a strength equal to or higher than that of conventional BMC and has degradability. It is to provide an improved molding material and molded part.

  In order to solve the above problems, the molding material of the present invention is characterized in that it contains at least a thermosetting resin containing an unsaturated polyester and a crosslinkable monomer and a plant-derived fiber.

  It is preferable that the plant-derived fiber is at least one selected from wood-based waste materials generated from bark, thinned wood, pruned branches, building waste materials, or palm-coconut palm shell waste materials and fibers derived from waste leaves and waste trunks. .

Moreover, it is preferable that the ratio of the plant origin fiber which occupies in a mold material is 0.5-20 wt%. It is also preferable that the plant-derived fiber is adjusted to a length of 1 to 5 mm.
A molded part produced using the above molding material also relates to the present invention.

  As described above, the molding material of the present invention can improve the strength of the molded body by including a thermosetting resin containing at least an unsaturated polyester and a crosslinkable monomer and a plant-derived fiber. Effective use of resources can be realized by taking out the plant-derived fiber from the waste material.

  Furthermore, since the molded body containing plant-derived fibers improves the permeability of aqueous solutions, the plant-derived fiber parts are easily decomposed, swollen, and softened, for example, by being immersed in an alkaline solution, and easily disintegrated when desired. Is possible. Therefore, disposal treatment such as volume reduction can be facilitated by treating the molded body that has become waste after use with an alkaline aqueous solution. In addition, since the polyester portion of the thermosetting resin skeleton is easily hydrolyzed by improving the permeability of the alkaline aqueous solution, the possibility of collapsing the three-dimensional structure of the resin is increased, and the disposal process can be made easier. it can. The permeability of the alkaline aqueous solution can be adjusted by changing the content of plant-derived fibers.

  Moreover, in the molded parts using the molding material, those having valuables inside, for example, mold motors or mold transformers having iron cores or windings, are disposed of an alkaline aqueous solution at the time of disposal. The mold part is swelled / softened, and further collapsed / peeled to allow the internal valuables to be taken out, and the reuse becomes easy.

Hereinafter, embodiments of the present invention will be described in detail.
In the molding material of the present invention, as the unsaturated polyester constituting the thermosetting resin, any unsaturated polyester composed of unsaturated polybasic acid, saturated polybasic acid, and glycols can be used as the main raw material.

  As the unsaturated polybasic acid, for example, maleic anhydride, fumaric acid, itaconic acid and the like are used. Examples of the saturated polybasic acid include phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, tetrabromophthalic anhydride, adipic acid, sebacic acid and the like. It is done.

  Examples of glycols include propylene glycol, ethylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, dibromoneopentyl glycol, 1,3-butanediol, 1,4-butanediol, hydrogenated bisphenol A, and the like. It is done.

  Examples of the crosslinkable monomer, that is, the addition polymerizable monomer serving as a crosslinking agent include styrene, methyl methacrylate, vinyl acetate, vinyltoluene, α-methylstyrene, methyl acrylate, 2-hydroxyethyl acrylate, and 2-hydroxyethyl methacrylate. Etc. Of these monomers, styrene is most preferred because it is inexpensive and has good crosslinkability.

  The crosslinkable monomer is preferably added 1.3 to 5 times in molar ratio to the unsaturated polybasic acid. If the molar ratio is 1.3 or less, the amount of unreacted unsaturated polybasic acid increases, and the strength of the molded article is reduced. If the molar ratio is 5 or more, a large amount of unreacted monomer may remain.

  As the polymerization initiator, for example, t-butyl perocate, benzoyl peroxide, t-butyl perbenzoate, 2,2, bis (t-butylperoxy) butane, 3,3,5, trimethyl (t-butylperoxide) Oxy) cyclohexane or the like may be added.

As the filler, it is sufficient if it contains at least plant-derived fibers, and other fillers may be mixed in consideration of fluidity and strength.
The plant-derived fiber is preferably at least one selected from wood-based waste materials generated from bark, thinned wood, pruned branches, construction waste materials, etc., or palm coconut shell waste materials, waste leaf / waste stem-derived fibers. .

  Among them, palm coconut shell waste and fibers derived from waste leaves and stems are preferable. Palm coconut shells, waste leaves, and waste trunks are mostly fibrous, and can be used as fibrous fillers simply by crushing.

  General wood-based waste can be crushed and used as a chip-like filler, but because it is not fibrous, it is difficult to improve the strength of the molding material. A material is preferred.

  For the pulverization treatment, a crusher, a cutter mill, a disk mill, or the like, which is a general pulverization apparatus, can be used in combination. For pulverization, the water content should be as small as possible, preferably 50% or less. Therefore, depending on the type of waste material, it may be better to perform a drying process in advance.

In order to mix a plant origin fiber with a thermosetting resin, it is necessary to dry beforehand. For drying, a constant temperature dryer or the like that is commonly used can be used.
The plant-derived fiber is preferably adjusted to a length of 1 to 5 mm. If it is too short, the effect of improving the strength of the molding material is reduced, and if it is too long, problems such as a decrease in fluidity and difficulty in kneading BMC occur.

  The proportion of plant-derived fibers in the mold material is preferably 0.5 to 20 wt%. 1.0-15 wt% is more preferable. If the added amount is too small, the effect of improving the strength is small, and if the added amount is too large, the amount of resin absorption increases, making it difficult to knead BMC or lowering the fluidity.

  Of course, an inorganic filler may be added in addition to the plant-derived fiber. Examples of the inorganic filler include calcium carbonate, calcium silicate, magnesium carbonate, barium sulfate, calcium sulfate, aluminum hydroxide, glass spheres and the like.

  Furthermore, polyacrylonitrile-based or rayon-based or pitch-based carbon fibers, vinylon, polypropylene, polyester, aramid fibers, or other organic fibers may be added as a reinforcing material. In some cases, glass fiber may be used in combination.

As the low shrinkage agent, for example, polystyrene, polycaprolactone, polydipropylene adipate, polydipropylene isophthalate and the like may be added.
As the colorant, general dyes and pigments can be used. For example, inorganic pigments such as iron oxide, titanium oxide, cadmium yellow, cadmium red, chrome yellow, chrome vermilion, ultramarine blue, azo compounds, cyanine blue, chlorine Organic pigments such as cyanine blue and cyanine green, dyes such as indigo red and oil red, carbon black and the like may be added.

As a thickener, for example, magnesium oxide, magnesium hydroxide, calcium hydroxide, a polyvalent isocyanate compound or the like may be added.
As the mold release agent, for example, a fluorine-based surfactant, zinc stearate, magnesium stearate and the like can be used.

  The molded component (molded product) of the present invention is molded by a transfer molding machine or the like using the above-described molding material. Examples of the molded part include a motor and a transformer.

  As a method for decomposing the molded product, for example, it is immersed in an alkaline aqueous solution (hereinafter simply referred to as a solution) containing an alkali metal compound or an alkaline earth metal compound having a concentration of 2 to 7N. As a result, the solution penetrates into the plant-derived fiber portion, causing actions such as decomposition, swelling, and softening, and the ester portion in the unsaturated polyester resin skeleton is also promoted to be easily decomposed. Yes. In particular, the solution having the above concentration gives sufficient hydroxide ions for hydrolysis, and the increase in viscosity due to the addition of an alkali metal compound or alkaline earth metal compound does not increase so much. Absent. For this reason, a molded object can be decomposed | disassembled in a short time.

  Examples of the alkali metal compound or alkaline earth metal compound include sodium hydroxide, potassium hydroxide, barium hydroxide, sodium ethoxide, potassium butoxide and the like. In the aqueous solution of these alkali metal compounds or alkaline earth metal compounds, the higher the concentration, the more the hydroxide ions increase, attacking the ester bond of the thermosetting polyester resin, and promoting the hydrolysis. Etc., the viscosity of the solution also increases, and the permeability of the solution into the resin decreases. Therefore, it is preferable that the concentration is such that a sufficient hydrolysis reaction occurs and the liquid permeability is not lowered. 10N or less is preferable, and 2 to 7N is particularly preferable. The alkali metal compound or alkaline earth metal compound is not limited to a single type, and a plurality of types may be included.

  In order to improve the permeability of the above solution to the resin, hydrophilic solvents such as alcohols such as methyl alcohol and ethyl alcohol, acetone, tetrahydrofuran, ethylene glycol, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl Ether, diethylene glycol, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, dimethylformamide, dimethylamine, and the like may be used.

  An alkaline aqueous solution generated by a water electrolysis apparatus may be used for the decomposition treatment. In that case, it is preferable to use an aqueous solution having a pH of 11 or more. If the pH is less than 11, sufficient hydrolysis reaction does not occur, and the treatment time may be long. When electrolyzing water, a small amount of sodium chloride, potassium chloride, calcium carbonate, calcium sulfate, sodium hydroxide, hydrochloric acid or the like may be added as an electrolyte. In particular, sodium chloride and potassium chloride are preferable in handling.

  Of course, the higher the processing temperature, the higher the decomposition rate, so it may be heated within the range below the boiling point of water (under 100 ° C at normal pressure), but it contains alcohols. Is preferably below their boiling point.

  The decomposition method is not limited to immersing in the alkaline aqueous solution, but may be acid treatment or solvent treatment. Such a decomposition method in which a liquid permeates to cause an action such as decomposition or swelling is preferable because the characteristics of the molding material and the molded part of the present invention can be utilized.

  Hereinafter, the present invention will be described in more detail with reference to specific examples.

  Take 100 parts by weight of a 7: 3 mixture of Dainippon Ink & Chemicals PB210 as an unsaturated polyester resin and PB987, which is a polystyrene-based low shrinkage agent, to obtain a polymerization initiator 1.1 dibutylperoxy-3. .1 part by weight of trimethylcyclohexane was added and mixed by stirring to obtain a resin liquid composition. The unsaturated polyester resin and the low shrinkage material contain styrene which is a crosslinkable monomer.

  The palm trunk was used as plant-derived fiber. The waste trunk cut out in a plate shape of 200 × 300 × 50 mm was coarsely pulverized to about several mm with a cutter mill VM-22 manufactured by Sugano Sangyo Co., Ltd. equipped with a screen of φ10 mm. Next, the coarsely pulverized product was further pulverized by a fine pulverizer DD-2-3.7 manufactured by Hadano Sangyo. The screen used was Φ3 mm. As a result, a fibrous filler having an average length of about 3 mm was obtained.

  Next, 28 parts by weight of calcium carbonate as another filler, 43 parts by weight of aluminum hydroxide, 1.4 parts by weight of zinc stearate as a release agent, and 0.3 parts by weight of carbon powder as a colorant are used as a kneader. Transfer and dry mix. After about 5 minutes, 21.2 parts by weight of the resin liquid composition was gradually added to the uniformly mixed dry mixture and kneaded for about 10 minutes.

Finally, the fibrous filler was added in an amount of 0 to 20 parts by weight with respect to the entire mold material, and several types of uniform paste-like mold materials were obtained.
As a comparative example, instead of the above fibrous filler, the glass fiber having a length of 3 mm was dispersed evenly and added in a short time as much as possible. A mold material was obtained.

  The fluidity of the obtained molding material was measured. The measuring method is as follows: a die having a spiral groove (die temperature: 145 ° C.) is attached to a transfer molding machine, molding is performed at a molding pressure of 5 MPa, a curing time of 120 sec, and a molding material input amount of 50 g, and the spiral from the center is performed. The length was read and the fluidity was evaluated as a spiral flow.

  Moreover, the molded object for a bending strength measurement of length 127mm, width 12.7mm, and thickness 3.2mm was created using the said transfer molding machine. The molding conditions are a mold temperature of 145 ° C. and a molding pressure of 5 MPa.

The bending strength of this molded body was measured at a test speed of 10 mm / min using an autograph manufactured by Shimadzu Corporation.
The results are summarized in (Table 1).

表１からわかるように、植物由来繊維の添加は従来のガラス繊維添加に比べて、流動性の低下は抑制しながら、ほぼ同程度の曲げ強度の向上がみられた。これは、植物繊維が樹脂とのなじみがよいためと考えられる。

As can be seen from Table 1, the addition of plant-derived fibers showed almost the same improvement in bending strength while suppressing a decrease in fluidity compared to the conventional glass fiber addition. This is presumably because the plant fibers are well compatible with the resin.

  Next, the molded body for measuring bending strength was immersed in a 5N aqueous sodium hydroxide solution at 80 ° C. for 10 hours, and then cut to measure the degree of penetration of the liquid. Here, the penetration degree of the liquid was simply determined by visual evaluation because the penetration degree visually evaluated from the change in the color of the penetrated portion and the penetration degree of sodium measured with an X-ray microanalyzer coincided. The results are shown in Table 2.

この結果より、ガラス繊維の代わりに植物由来繊維を添加すると、アルカリ性溶液の浸透度が大きくなることがわかる。また、液が浸透した部分は軟らかくなっていて、手で容易にぼろぼろに崩壊させることができた。

From this result, it can be seen that when plant-derived fibers are added instead of glass fibers, the permeability of the alkaline solution increases. Further, the portion where the liquid penetrated was soft and could be easily broken down by hand.

  By using such a decomposition method by the permeation of liquid, the molded body can be easily decomposed. When there is a valuable material inside the mold, the valuable material can be easily taken out and recycled.

  The plate-shaped cedar wood was roughly pulverized to a few millimeters by the same pulverizer as in Example 1. This pulverized product was immersed in a caustic soda cooking solution, heated and pressurized to separate the fibers, washed and dried, and used as the fibrous filler of the molding material.

The plant-derived fiber was changed to the fiber of Example 1, and the other molding material was prepared under the same conditions. In addition, the addition amount of the plant origin fiber was adjusted to 10 wt%.
As a result, the spiral flow was 175 cm, the bending strength was 45.5 MPa, and the strength could be improved while suppressing a decrease in fluidity as in the case of palm palm waste trunk.

  Moreover, when the immersion treatment was performed in a 5N sodium hydroxide aqueous solution under the same conditions as in Example 1, the liquid had completely penetrated into the molded body and could be easily broken down by hand.

  The molding material of the present invention to which plant-derived fibers are added can provide the same degree of strength improvement to the molded product while suppressing a decrease in fluidity compared to the conventional glass fiber-added molding material, and is alkaline. It can be easily decomposed by immersing it in an aqueous solution. Therefore, it can be suitably used for a mold motor, a mold transformer, and the like, and valuable materials inside the mold can be recycled.

Claims (5)

  A molding material comprising a thermosetting resin containing at least an unsaturated polyester and a crosslinkable monomer and a plant-derived fiber.   2. The plant-derived fiber according to claim 1, wherein the plant-derived fiber is at least one selected from a wood-based waste material generated from bark, thinned wood, pruned branches, construction waste material, or the like, or palm coconut shell waste material, waste leaf / waste stem-derived fiber The mold material characterized by being.   The mold material according to claim 1 or 2, wherein a ratio of plant-derived fibers in the mold material is 0.5 to 20 wt%.   4. The molding material according to claim 1, wherein the plant-derived fiber is adjusted to a length of 1 to 5 mm.   A molded part produced using the molding material according to claim 1.