JP4098339B2 - Master batch for plastic dehumidification and dehumidification method of plastic material - Google Patents

Description

  The present invention relates to a plastic dehumidification masterbatch and a method for producing a plastic dehumidification masterbatch.

  In various plastic molding methods such as injection molding, extrusion molding, and T-die method, when a plastic material containing water is heated and melted and molded, the water vaporizes by heating, so that the surface of the molded product is swollen. It tends to cause fogging, cloudiness, or appearance defects such as a water pattern or fish eye. Such a defect in the appearance of the molded product may occur even if the plastic material contains only about 0.5% by weight of water. Therefore, when molding a plastic material, the plastic material is generally used after being dried in advance (so-called preliminary drying). In particular, pre-drying is indispensable when molding highly hygroscopic plastic materials such as ABS resin (acrylonitrile / butadiene / styrene copolymer), nylon, polymethyl methacrylate, and polyvinyl chloride. .

  In addition, plastic materials having an ester bond in the molecule, such as polyethylene terephthalate, polybutylene terephthalate, and polycarbonate, are hydrolyzed and reduced in molecular weight when heated and melted while containing moisture. There is a risk of physical properties such as a decrease in strength. Therefore, in these plastic materials, preliminary drying is indispensable not only for preventing defects in appearance of molded products but also for preventing physical properties.

  The plastic material is generally pre-dried by a dryer such as a hot air dryer. The drying conditions vary depending on the type of plastic material, but generally it takes about 2 to 4 hours in a temperature range of about 70 to 150 ° C. A plastic material having a high hygroscopic property requires a longer drying time. For example, nylon 6 is preliminarily dried at 80 ° C. for 8 hours or more.

  By the way, various types of master batches have been conventionally used for molding plastics, and master batches containing hygroscopic agents or additives having hygroscopic properties have already been disclosed. For example, Patent Literature 1 discloses a master batch containing a hygroscopic agent. This masterbatch is a masterbatch used for adding a hygroscopic agent to a plastic material when producing a plastic molded product that exhibits hygroscopicity by the internally added hygroscopic agent. When the hygroscopic agent absorbs moisture when manufacturing the master batch or storing the master batch, the hygroscopic property of the molded article is lowered, and the hygroscopic agent is difficult to disperse in the plastic material when molding the plastic material. Therefore, this masterbatch has a structure that prevents the hygroscopic agent in the central part from absorbing moisture during manufacture and storage of the masterbatch by covering the central part made of the thermoplastic resin and the hygroscopic agent with the outer layer of the thermoplastic resin. It has become.

  Patent Document 2 discloses a master batch containing alumina. This masterbatch is a coloring masterbatch that is used to add a colorant to a plastic material when producing a colored molded article, and contains alumina, a silane coupling agent, etc. in addition to the colorant. ing. Alumina is generally hygroscopic although it is contained in this masterbatch to improve the physical properties of the molded product.

JP 2005-7837 A Japanese Patent Laid-Open No. 10-45919

  As described above, in the past, pre-drying of a plastic material has become common sense as indispensable in the molding process of plastic having hygroscopicity or containing a certain amount of moisture. However, in the conventional preliminary drying, the plastic material is dried using a dryer, and thus there is a problem that a great deal of energy and time are required. Further, when the plastic material is excessively long or heated at an excessively high temperature in the preliminary drying, there is a problem that the plastic material is deteriorated due to discoloration or deterioration of physical properties.

  On the other hand, although there is a master batch containing a hygroscopic agent and a hygroscopic alumina, there has been no master batch for dehumidifying the plastic material at the time of molding instead of preliminary drying by a dryer. In order to dehumidify the plastic material by the masterbatch, at least when the masterbatch is mixed with the plastic material, it is necessary that the hygroscopic agent is dispersed in the plastic material in a state where it can sufficiently absorb moisture and spreads thoroughly. Therefore, it has been difficult to divert master batches that have been used in different applications. For example, the masterbatch described in Patent Document 1 contains a hygroscopic agent, and in order to suppress moisture absorption of the hygroscopic agent during production and storage of the masterbatch, the central portion containing the hygroscopic agent is used as an outer layer of a thermoplastic resin. It has a double structure that covers it. However, although the moisture permeability of the thermoplastic resin differs depending on the type, the type of the thermoplastic resin constituting the master batch is generally limited by the compatibility with the added plastic material. Therefore, depending on the type of thermoplastic resin that makes up the masterbatch, moisture absorption during the production and storage of the masterbatch cannot be sufficiently suppressed, and the hygroscopic performance of the hygroscopic agent decreases before mixing with the plastic material. There is a possibility that the molded product cannot fully exhibit the moisture absorbing function. In addition, the hygroscopic agent is usually an inorganic compound, and no treatment for improving the dispersibility has been performed despite the lack of compatibility with the plastic material, and the hygroscopic agent is thoroughly dispersed in the plastic material. It is difficult. Therefore, the masterbatch described in Patent Document 1 cannot be used for dehumidification of plastic materials. On the other hand, the masterbatch described in Patent Document 2 contains alumina that can absorb moisture, and in addition, generally contains a silane coupling agent that improves the compatibility between the plastic material and the inorganic compound. Easy to disperse in plastic material. However, in the masterbatch described in Patent Document 2, it is not considered at all to suppress the moisture absorption of alumina before use, and the moisture absorption performance may be deteriorated due to the moisture absorption of alumina before mixing with the plastic material. There is. Therefore, the masterbatch described in Patent Document 2 cannot be diverted for dehumidification of plastic materials.

  Therefore, the present invention is capable of dehumidifying a plastic material in a short time and with low energy without heating for the purpose of drying, and is capable of molding the plastic material without preliminary drying by a dryer. The problem was to provide a masterbatch for use.

In order to solve the above problems, the following measures are taken.
First, the first invention is a masterbatch that is mixed when the plastic material is molded and heated together with the plastic material and melts with the plastic material, and includes a dehumidifying agent and a thermoplastic resin as a binder, The dehumidifying agent improves the compatibility between the inorganic compound and the thermoplastic resin by covering the surface of the inorganic compound with a hygroscopic powder and the inorganic compound, and also has a hygroscopic function of the inorganic compound at room temperature. A plastic dehumidification masterbatch that absorbs moisture contained in the plastic material during molding of the plastic material, comprising a surface modifier that suppresses and exhibits a moisture absorption function of the inorganic compound when heated. The inorganic compound is a chemically hygroscopic inorganic compound that absorbs moisture by a chemical reaction with moisture, and in addition to a dehumidifying agent composed of the chemically hygroscopic inorganic compound, further, an adsorptive inorganic compound that absorbs moisture by adsorbing moisture It also contains a dehumidifier composed of The chemically hygroscopic inorganic compound is calcium oxide, and the adsorptive inorganic compound is zeolite. The surface modifier is at least one selected from the group consisting of titanate coupling agents, aluminate coupling agents, and stearic acids. The ratio of the dehumidifying agent contained in the master batch is 20% by weight or more and 90% by weight or less.

Next, the second invention contains a dehumidifying agent and a thermoplastic resin as a binder, and the dehumidifying agent covers the inorganic compound powder and the inorganic compound powder having a hygroscopic property. A surface-modifying agent that improves the compatibility of the compound with the thermoplastic resin and suppresses the hygroscopic function of the inorganic compound at room temperature, and the inorganic compound absorbs moisture by a chemical reaction with moisture. compounds and Ri adsorbing inorganic compound der to moisture absorption by adsorbing moisture, the chemical hygroscopic inorganic compound is calcium oxide, the adsorbing inorganic compound is a zeolite, the surface modifier is a titanate coupling agent , An aluminate coupling agent, and at least one selected from the group consisting of stearic acids, and included in the master batch of the dehumidifying agent. Ratio of masterbatch moisture plastic removal or less 90 wt% 20 wt% or more, was added to the plastic material during the molding of plastic materials, plastic materials by exerting moisture function of the inorganic compound by heating during the molding This is a method of dehumidifying a plastic material that removes moisture in the inside.

According to the plastic dehumidification masterbatch of the first invention (hereinafter sometimes simply referred to as “masterbatch”), the following operational effects can be obtained.
First, since it contains a dehumidifying agent, the plastic material can be easily dehumidified by dispersing the dehumidifying agent in the plastic material simply by mixing the plastic material when it is molded.

  Secondly, the dehumidifying agent is coated with an inorganic compound with a surface modifier that improves the compatibility with the thermoplastic resin, and the dehumidifying agent is formed in the thermoplastic resin when the master batch is manufactured. Easy to disperse. Therefore, the dehumidifying agent can be uniformly contained in the master batch, and by definitely mixing the master batch with the plastic material, the dehumidifying agent can be reliably mixed with the plastic material to dehumidify.

  Third, the surface modifier constituting the dehumidifying agent suppresses the hygroscopic function of the inorganic compound at room temperature by coating the hygroscopic inorganic compound, and exerts the hygroscopic function of the inorganic compound during heating. Is difficult to absorb moisture when stored at room temperature before use, and easily absorbs moisture when heated with a plastic material during use. Therefore, this masterbatch preserves the hygroscopic function of the inorganic compound before use, and when used, the hygroscopic function of the inorganic compound is reliably exerted to dehumidify the plastic material.

  Fourth, since the dehumidifying agent is difficult to absorb moisture at room temperature, the dehumidifying function of the dehumidifying agent is not easily impaired even if the master batch is exposed to a normal humidity environment during storage or preparation for use.

According to the master batch of the first invention, the plastic material can be easily dehumidified by mixing with the plastic material when molding the plastic material. The step of pre-drying the plastic material in the molding step can be omitted. Therefore, the molding process of the plastic material can be shortened, and the plastic material can be molded in a shorter time and with lower energy than before. Further, since it is not necessary to heat the plastic material only for preliminary drying, the plastic material can be prevented from being overheated and deteriorated. In addition, since the inorganic compound constituting the dehumidifying agent is a chemically hygroscopic inorganic compound that absorbs moisture by a chemical reaction with moisture, the moisture absorbing function can be surely exhibited even under heating conditions, and the chemical hygroscopic component constituting the dehumidifying agent Since the water-soluble inorganic compound has excellent reactivity with moisture, moisture in the plastic material can be removed more efficiently. Therefore, when heated together with the plastic material, the moisture absorption function can be surely exhibited, and moisture in the plastic material can be more reliably removed. In addition, in addition to a dehumidifying agent composed of a chemically hygroscopic inorganic compound, and further containing a dehumidifying agent composed of an adsorptive inorganic compound that absorbs moisture by adsorbing moisture, The moisture absorption at room temperature of the constructed dehumidifier can be more reliably suppressed. In addition, since the adsorptive inorganic compound is porous and excellent in adsorptivity at room temperature, moisture absorption at room temperature of the dehumidifier composed of the chemically hygroscopic inorganic compound can be reliably suppressed. Therefore, the preservation time of the hygroscopic function of the dehumidifying agent composed of the chemically hygroscopic inorganic compound can be further extended. Therefore, the hygroscopic function of the chemically hygroscopic inorganic compound can be preserved for a longer period before using the masterbatch. Further, since the surface modifier is at least one selected from the group consisting of titanate coupling agents, aluminate coupling agents, and stearic acids, the dehumidifying agent is excellent in compatibility with the thermoplastic resin. Thereby, the dehumidifying agent can be easily dispersed in the thermoplastic resin and the plastic material.

  The plastic dehumidification masterbatch of the present invention is a masterbatch that is used when molding a plastic material to dehumidify the plastic material. This master batch contains at least a dehumidifying agent and a thermoplastic resin as a binder as basic components. When this master batch is mixed with the plastic material when molding the plastic material, the thermoplastic resin and the plastic material are melted by the heating during molding, and the dehumidifying agent is dispersed in the plastic material to absorb moisture in the plastic material. be able to.

  The dehumidifying agent constituting the master batch is composed of a powder of an inorganic compound having hygroscopicity and a surface modifier for coating the surface of the inorganic compound.

  The surface modifier that constitutes the dehumidifying agent coats the surface of each particle of the inorganic compound to improve the compatibility between the inorganic compound and the thermoplastic resin, and suppresses the moisture absorption function of the inorganic compound at room temperature. It is a substance that demonstrates the hygroscopic function of inorganic compounds. As used herein, “suppressing the hygroscopic function of an inorganic compound” means inhibiting the hygroscopic function of the inorganic compound, and “exhibiting the hygroscopic function of an inorganic compound” almost inhibits the hygroscopic function of the inorganic compound. It means not. As such a surface modifier, for example, titanate coupling agents, aluminum coupling agents, paraffin, stearic acid, and the like can be used. These surface modifiers have affinity for both the inorganic compound and the thermoplastic resin, and are chemically or physically bonded to the surface of the inorganic compound powder to thereby bind the inorganic compound and the thermoplastic resin. The compatibility with can be improved. Further, by heating in contact with the inorganic compound and covering the entire surface of the inorganic compound, the hygroscopic function of the inorganic compound can be suppressed at room temperature, and the hygroscopic function of the inorganic compound can be reliably exhibited during heating. Although the theoretical basis is not necessarily clear, these surface modifiers are in a state in which the tissue is difficult for water molecules to pass through at room temperature, and changes to a state in which the water molecules can pass through heating so that the water molecules can pass through. It is considered a thing. A surface modifier is not limited to these, Moreover, only 1 type may be used independently and may be used in combination of 2 or more types.

  A conventionally well-known thing can be used as said titanate coupling agent. For example, isopropyl triisostearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, tetraoctyl bis (ditridecyl phosphite) titanate, bis (dioctyl pyrophosphate) oxyacetate titanate and the like can be used. A conventionally well-known thing can be used as said aluminum type coupling agent. For example, aluminum isopropylate, aluminum ethylate, aluminum tris (ethyl acetoacetate), ethyl acetoacetate aluminum diisopropylate and the like can be used. A conventionally well-known thing can be used as said paraffin. For example, liquid paraffin, paraffin wax, polyethylene wax and the like can be used. As the stearic acid, stearic acid and salts of stearic acid such as calcium stearate and magnesium stearate can be used.

  The ratio of the surface modifier contained in the dehumidifying agent is preferably a ratio sufficient to cover at least the entire surface of the inorganic compound powder in order to suppress the hygroscopic function of the inorganic compound at room temperature. Therefore, the proportion of the surface modifier can be appropriately set depending on the surface area of the inorganic compound, but in general, the proportion of the surface modifier relative to 100 parts by weight of the inorganic compound is 1 part by weight or more and 40 parts by weight or less, preferably 1 part by weight. Part to 10 parts by weight, more preferably 1 part to 5 parts by weight. When the amount of the surface modifier is larger than 40 parts by weight with respect to 100 parts by weight of the inorganic compound, the compatibility between the inorganic compound and the thermoplastic resin is not so much improved with respect to the addition amount of the surface modifier, and dehumidification is performed in the masterbatch. Since the agent may aggregate, it is not preferable. When the amount is 1 part by weight or more and 5 parts by weight or less, the dehumidifying agent can be uniformly dispersed in the master batch more efficiently.

  The inorganic compound constituting the dehumidifying agent is a powdery inorganic compound having hygroscopicity, and a chemically hygroscopic inorganic compound that absorbs moisture by a chemical reaction with moisture or an adsorptive inorganic compound that absorbs moisture by adsorbing moisture is used. be able to. Only one type of inorganic compound may be used alone, or two or more types may be used in combination. Preferably, at least one chemical hygroscopic inorganic compound is used. If a chemically hygroscopic inorganic compound is used, it can absorb moisture more reliably under heating conditions. More preferably, a chemically hygroscopic inorganic compound and an adsorptive inorganic compound are used in combination. Although the moisture absorption of the inorganic compound is suppressed by the surface modifier at room temperature, it is actually not completely inhibited and gradually absorbs moisture. However, the combined use of the chemically hygroscopic inorganic compound and the adsorptive inorganic compound can more reliably suppress the moisture absorption of the chemically hygroscopic inorganic compound at room temperature, and the master batch can be stored for a long time. . The theoretical basis for this is not necessarily clear, but it is considered that the adsorptive inorganic compound absorbs moisture preferentially over the chemically hygroscopic inorganic compound at room temperature.

  Examples of the chemically hygroscopic inorganic compound include calcium oxide, barium oxide, and aluminum oxide. These inorganic compounds can be preferably used because they are highly reactive with moisture and quickly absorb moisture, and among these, calcium oxide is highly safe and can be most preferably used. The chemically hygroscopic inorganic compound used in the present invention is not limited to these as long as it is an inorganic compound that absorbs moisture by a chemical reaction with moisture. Besides, calcium chloride, magnesium chloride, magnesium sulfate, calcium sulfate Etc. can also be used.

  Examples of the adsorptive inorganic compound include zeolite, silica gel, diatomaceous earth, and the like. Since these are porous and excellent in hygroscopicity, they can be suitably used. The adsorptive inorganic compound used in the present invention is not limited to these as long as it is an inorganic compound that absorbs moisture by adsorbing moisture.

  The inorganic compound powder preferably has a particle size of 20 μm or less. If the particle size is 20 μm or less, not only the surface area per unit weight is large and the dehumidification efficiency is good, but also when added to a plastic material, the moldability is impaired or the physical properties and appearance of the resulting molded body are deteriorated. There is nothing. More preferably, the particle diameter is 3 μm or more and 10 μm or less. Note that the particle size of 20 μm or less does not necessarily mean that the particle size of all inorganic compound powders is 20 μm or less. For example, if the particle size of 97% or more of the powder is 20 μm or less, An effect can be obtained. The particle diameter can be measured with a laser particle diameter measuring instrument, and the major axis of the measured particle can be used as the particle diameter.

  The proportion of the dehumidifying agent contained in the master batch is preferably 5% by weight or more and 90% by weight or less. If it is less than 5% by weight, a large amount of master batch must be added to remove moisture contained in the plastic material, which is not preferable. On the other hand, if it exceeds 90% by weight, the moldability of the master batch deteriorates, which is not preferable. More preferably, it is 20 to 80% by weight, and most preferably 40 to 60% by weight.

  The master batch of the present invention contains a thermoplastic resin. This thermoplastic resin functions as a binder that binds the dehumidifying agent and other components contained in the masterbatch to each other, and is sometimes referred to as a carrier resin. Examples of the thermoplastic resin used in the present invention include ABS resin (acrylonitrile butadiene styrene), polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, SBS (styrene butadiene styrene copolymer), EVA (polyvinyl alcohol). ), Polyoxyethylene, nylon, polystyrene, polybutylene terephthalate and the like. The thermoplastic resin used in the present invention is not limited to these, and other types of thermoplastic resins can also be used.

  It is preferable to use a thermoplastic resin having good compatibility with the plastic material to which the masterbatch is added. More preferably, a thermoplastic resin of the same type as the plastic material to which the master batch is added is used. For example, when the plastic material to which the masterbatch is added is an ABS resin, it is most preferable to use the same type of ABS resin as the thermoplastic resin used in the masterbatch, which is compatible with the ABS resin. SBS or EVA can also be preferably used. Only one type of thermoplastic resin may be used alone, or two or more types may be used in combination.

  The ratio of the thermoplastic resin contained in the masterbatch of the present invention is preferably 90% by weight or less. More preferably, it is 40 wt% or more and 60 wt% or less. If the ratio of a thermoplastic resin is this range, the moldability at the time of manufacturing a masterbatch will become favorable.

  In addition to the dehumidifying agent and the thermoplastic resin, the plastic dehumidifying master batch of the present invention may contain additives such as a lubricant, a plasticizer, a heat stabilizer, an antioxidant, and the like.

  A lubricant can be added to the masterbatch of the present invention. Thereby, in the manufacturing process of a masterbatch, while the moldability of a masterbatch is stabilized, friction with the said plastic material at the time of adding a masterbatch to a plastic material can be reduced. A conventionally well-known thing can be used as a lubricant. Only one type of lubricant may be used alone, or two or more types may be used in combination. Specific examples of the lubricant used in the present invention include, but are not limited to, the following.

  Examples of the lubricant include hydrocarbon lubricants such as liquid paraffin, paraffin wax and polyethylene wax, fatty acid lubricants such as stearic acid, metal soap lubricants such as calcium stearate, zinc stearate, magnesium stearate and zinc stearate. It can be illustrated. Among these, stearic acid is preferably used because it has excellent compatibility with various thermoplastic resins.

  The ratio of the lubricant contained in the master batch is preferably 15% by weight or less. When the lubricant is contained in an amount of more than 15% by weight, when the masterbatch is formed, the constituent materials of the masterbatch slip each other, so that the moldability is deteriorated. The ratio of the lubricant is more preferably 3% by weight or more and 6% by weight or less. When the ratio of the lubricant is within this range, the lubricity between the constituent materials can be improved and the moldability can be kept good when the master batch is molded. Further, when the masterbatch is added to the plastic material, friction between the masterbatch and the plastic material can be moderated moderately.

  A plasticizer can be added to the masterbatch of the present invention, whereby the moldability of the masterbatch can be further improved. Any plasticizer may be used as long as it is compatible with the thermoplastic resin contained in the masterbatch, and various plasticizers used for plastic molding can be used. Only one type of plasticizer may be used alone, or two or more types may be used in combination. Specific examples of the plasticizer include, but are not limited to, the following.

  Examples of the plasticizer include phthalate plasticizers such as diheptyl phthalate (DHP), di-2-ethylhexyl phthalate (DOP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), and di-2 adipate. Aliphatic dibasic acid esters such as ethylhexyl (DOA), diisononyl adipate (DINA), di2-ethylhexyl sebacate (DOS), epoxidized soybean oil, epoxidized linseed oil, butyl epoxystearate, dioctyl epoxyhydrophthalate, Examples thereof include an epoxy plasticizer such as bisphenol A diglycidyl ether. Among these, phthalate ester plasticizers are excellent in compatibility with various thermoplastic resins and have good heat resistance and cold resistance, and therefore can be suitably used. The proportion of the plasticizer contained in the master batch is preferably 50% by weight or less. More preferably, they are 3 weight% or more and 8 weight% or less.

  A heat stabilizer can be added to the master batch of the present invention, thereby preventing discoloration of the thermoplastic resin due to heating during molding of the master batch. As the heat stabilizer, various heat stabilizers used in plastic molding can be used. Only one type of heat stabilizer may be used alone, or two or more types may be used in combination. Specific examples of the heat stabilizer include, but are not limited to, the following.

  Examples of the heat stabilizer include aliphatic carboxylate lithium stearate, magnesium stearate, calcium laurate, calcium linoleate, calcium stearate, barium ricinoleate, barium stearate, zinc laurate, zinc ricinoleate, and zinc stearate. Aliphatic carboxylate heat stabilizers, dimethyltin bis-2-ethylhexyl thioglycolate, organic tin mercaptides such as mono / dimethyltin stearoxyethyl mercaptide, dibutyltin maleate, dibutyltin bisbutyl maleate, Organic tin maleates such as dibutyltin dilaurate, dibutyltin bis-2-ethylhexylthioglycolate, dibutyltin β-mercaptopropionate, and dioctyltin dilaurate, dioctylus It may be exemplified various organic tin-based heat stabilizers organotin carboxylates such as bis-2-ethylhexyl thioglycolate. The proportion of the heat stabilizer contained in the master batch is preferably 10% by weight or less. More preferably, it is 1 wt% or more and 3 wt% or less.

  An antioxidant can be added to the masterbatch of the present invention, whereby the thermoplastic resin can be prevented from being oxidized by heating during production of the masterbatch and deteriorating in quality. Any antioxidant can be used as long as it has compatibility with the thermoplastic resin contained in the masterbatch, and various antioxidants generally used for plastic molding can be used. Only one type of antioxidant may be used alone, or two or more types may be used in combination. Specific examples of the antioxidant include, but are not limited to, the following.

  Examples of the antioxidant include 2,6-di-t-butyl-4-methylphenol, n-octadecyl-3- (3 ′, 5′-di-t-butyl-4′hydroxyphenyl) propionate, tetrakis- [Methylene-3- (3 ′, 5′-di-t-butyl-4-hydroxyphenyl) propionate] methane, tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, triethylene glycol -Bis- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], 2,2'-methylenebis- (4-methyl-6-tert-butylphenol), 4,4'-thiobis Phenolic antioxidants such as-(3-methyl-6-t-butylphenol), 4,4'-butylidenebis- (3-methyl-6-t-butylphenol) Agent, dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiocypropionate, distearyl-3,3′-thiodipropionate, pentaerythritol tetrakis (3-laurylthiopropionate ) And the like, trisnonylphenyl phosphite, distearyl pentaerythritol diphosphite, tris (2,4-di-t-butylphenyl) phosphite, tetrakis (2,4-di-t-butyl) And phosphoric acid antioxidants such as phenyl) -4,4′-biphenylene-di-phosphite. The proportion of the antioxidant contained in the master batch is preferably 15% by weight or less. In addition, although the mixing | blending ratio standard of a dehumidifying agent, a thermoplastic resin, and various additives was shown, it cannot be overemphasized that it should prepare within the range which adds them all and becomes 100 weight%.

  Hereinafter, the manufacturing method of the masterbatch of this invention is demonstrated. The master batch of the present invention can be manufactured through the following first to third steps.

[First step]
First, in the first step, the inorganic compound powder and the surface modifier are mixed while heating, whereby the surface of the inorganic compound is coated with the surface modifier to obtain a dehumidifying agent. The heating temperature at this time is preferably 90 ° C. or higher and 130 ° C. or lower. Various agitators having a heating function can be used for mixing. For example, a jacketed Nauter mixer, ribbon mixer, Henschel mixer, super mixer, etc. can be used and mixed while heating by passing heated oil through the jacket.

[Second step]
Next, in the second step, first, the dehumidifying agent obtained in the first step is cooled to 40 ° C. or lower. Here, the cooling may be active cooling such as flowing cold water through the jacket of the stirrer, or may be allowed to cool. Next, the cooled dehumidifying agent is mixed with a thermoplastic resin and various additives (such as a lubricant, a plasticizer, a heat stabilizer, and an antioxidant) as necessary. Various agitators can be used for mixing as in the first step.

[Third step]
Next, in the third step, the mixture obtained in the second step is heated to 90 ° C. or higher and 220 ° C. or lower and formed into a predetermined shape such as a dice shape, a cylindrical shape, a spherical shape, a flat spherical shape, or the like, and a master batch. Get. In the third step, various extruders capable of being heated and kneaded can be used. In particular, it is preferable to use a twin screw extruder because a master batch having a good appearance in which inorganic compound powders are uniformly dispersed can be obtained. If it is a twin screw extrusion machine provided with a vacuum function, the volatile component which generate | occur | produces by heating a mixture can be removed, and a masterbatch with a better external appearance can be obtained.

  The plastic dehumidification masterbatch of the present invention can be used by mixing with various plastic materials. For example, ABS resin, nylon, polymethyl methacrylate, polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, etc. can be used even if added to a thermoplastic resin that requires particularly careful pre-drying in conventional methods. be able to. Further, it can be used by being added to a wet thermoplastic resin due to inappropriate storage or the like. Further, it can be used by adding to a recycled resin (recycled resin) using a used plastic bottle or the like.

  The plastic material molding method using the plastic dehumidification masterbatch of the present invention will be described below. First, the master batch of the present invention is added to a plastic material. It is preferable to use a master batch in which the thermoplastic resin contained in the master batch is compatible with the plastic material to which the master batch is added. It is more preferable if the thermoplastic resin contained in the masterbatch is the same type as the plastic material to which the masterbatch is added. The proportion of the masterbatch added to the plastic material can be appropriately determined depending on the moisture content of the plastic material, but it is usually 6% by weight or less. In addition to the master batch, various additives such as a plasticizer, a heat stabilizer, and an antioxidant can be added to the plastic material as necessary.

  Next, the plastic material to which the master batch has been added is molded by various known molding methods such as an extrusion molding method, an injection molding method, and a T-die method. Generally, when molding a plastic material, the plastic material is heated and melted. When the plastic material is heated, the plastic material and the master batch are melted together, and the dehumidifying agent contained in the master batch is dispersed in the plastic material. At this time, since the inorganic compound powder is covered with the surface modifier, the dehumidifier has an affinity for the plastic material and is uniformly dispersed in the plastic material. Moreover, by heating with it, suppression of the hygroscopic function of the inorganic compound by the surface modifier is released, and the hygroscopic function of the inorganic compound is exhibited. As a result, the dehumidifying agent spreads quickly to every corner of the plastic material, and moisture in the plastic material can be efficiently absorbed and removed. Therefore, if the master batch of the present invention is used, the plastic material can be molded without pre-drying.

  The molded body thus obtained has no appearance defect or the like due to evaporation of moisture, even though the plastic material as a raw material has not been pre-dried. In addition, since heating for preliminary drying is unnecessary, discoloration of plastic materials and deterioration of physical properties due to overdrying are not caused. Moreover, since it is not necessary to heat for a long time for preliminary drying, the plastic material can be molded in a short time and with less energy. As a result, it is possible to realize a molded body of a plastic material that is low in cost and is environmentally friendly.

The following No. No. 1 to 10 master batches. 6 and 10 correspond to examples.
Calcium oxide powder of particle size 10μm as free machine compounds, stearic acid as a surface modifier, polyethylene as a thermoplastic resin, prepared polyethylene wax as a lubricant, through the first to third step No. 1 masterbatch was created. The composition ratio is shown in Table 1. Polyethylene wax not only functions as a lubricant, but also functions as a dispersant for dispersing calcium oxide powder in a thermoplastic resin, and also functions as a plasticizer.

  The prepared master batch (No. 1) was added to polyethylene resin pellets that had not been pre-dried and contained 1% by weight of water, and a film was formed by the T-die method. As a result, a polyethylene film having no defects in appearance could be obtained. Further, the master batch (No. 1) was added to a recycled polyethylene resin pellet not containing any pre-dried water containing 0.5% by weight of water, and a film was formed by the T-die method. As a result, it was possible to obtain a recycled polyethylene film having no defects in appearance.

Calcium oxide powder of particle size 8μm as a free machine compounds, stearic acid as a surface modifier, a thermoplastic resin as ABS resin and SBS, lubricants as magnesium stearate and EBS (ethylene-bis-stearic acid amide), DOP (phthalic as a plasticizer Acid di-ethylhexyl), and after passing through the above first to third steps, No. 1 was prepared. Two masterbatches were created. The composition ratio is shown in Table 2.

  The prepared master batch (No. 2) was added within a range of 1% by weight or more and 2% by weight or less with respect to the ABS resin not preliminarily dried, and molded by an injection molding method. As a result, it was possible to obtain a molded article of ABS resin having no defect in appearance.

Calcium oxide powder of particle size 8μm as free machine compounds, stearic acid as a surface modifier, SBS thermoplastic resin, a lubricant as magnesium stearate, and polyethylene wax, prepared calcium carbonate as a filler, in proportions shown in Table 3 No. 3 and no. 4 masterbatches were created. In addition, No. No. 3 creates a master batch through the above first to third steps. 4 omits the first step in the above first to third steps, and added calcium oxide in the second step to prepare a masterbatch. Next, each master batch was allowed to stand in a natural environment for 24 hours and then visually observed to examine changes in size and color. Further, 6% by weight of a master batch that was allowed to stand in a natural environment for 24 hours was mixed with 94% by weight of ABS resin, and injection molded to obtain a container. The obtained container was visually observed to check for defects in appearance. The results are shown in Table 3.

  No. No. 3 master batch and No. 3 The aspect of the inorganic compound contained in the masterbatch 4 is different. That is, no. In No. 3, the inorganic compound is covered with the surface modifier, whereas No. 4 is different in that the inorganic compound is not covered with a surface modifier and is contained naked. First, when the appearance of a container prepared by adding a masterbatch that was allowed to stand for 24 hours in a natural environment was compared, The surface of the container of No. 3 is smooth and free from defects. The container of No. 4 had a water-like pattern on its surface. This is no. No. 3 master batch sufficiently dehydrated the water in the ABS resin, It is inferred that the master batch No. 4 was not able to completely dehumidify the moisture in the ABS resin, and the moisture remaining in the ABS resin was vaporized to form a water-pattern pattern on the surface of the container. Next, when the appearances of the master batches after being allowed to stand for 24 hours are compared, no. No. 3 has no change, while No. 3 4 is expanded and whitened. As a result, no. No. 3 masterbatch contained almost no inorganic compound (calcium oxide). It is surmised that the inorganic compound contained in the master batch No. 4 absorbed a large amount of moisture in the air. From the above, when the inorganic compound is not covered with the surface modifier (No. 4), the moisture in the air is absorbed during storage and the moisture absorption function is remarkably reduced, and the moisture in the ABS resin is sufficiently used during use. It became clear that it could not be absorbed. On the other hand, when the inorganic compound is covered with a surface modifier (No. 3), the moisture absorption function of the inorganic compound is preserved in a normal natural environment. It was revealed that the ABS resin can be sufficiently dehumidified.

Zeolite calcium oxide powder and particle size 10μm particle size 10μm as free machine compounds, stearic acid as a surface modifier, polyethylene as a thermoplastic resin, prepared polyethylene wax as a lubricant, through the first to third step No. 5 and no. Six master batches were created. The composition ratio is shown in Table 4. Next, the obtained master batch No. 5 and no. After leaving 6 in a natural environment for 36 hours, the master batches were mixed with regenerated polyethylene resin containing 0.5% by weight of water which had not been pre-dried to form a film. At this time, the master batch was added to the recycled polyethylene resin so that the master batch was 3% by weight. The obtained film was observed visually to investigate the presence or absence of defects in appearance. In this survey, the appearance defect caused by water volatilization during molding, such as a water-like appearance defect, is referred to as a “water-pattern defect”, and the appearance defect due to the generation of particulate impurities is referred to as a “particle-like defect”. As for each, the presence or absence was confirmed. The results are shown in Table 4.

  No. No. 5 master batch and No. 5 In the master batch of No. 6, the inorganic compounds constituting the dehumidifying agent are different. That is, no. No. 5 contains only one kind of calcium oxide, which is a chemically hygroscopic inorganic compound, whereas 6 differs in that it contains zeolite, which is an adsorptive inorganic compound, in addition to calcium oxide. None of the films formed using the masterbatch that was allowed to stand for 36 hours before use had water-pattern defects. From this, it can be seen that the moisture absorption function of each master batch was suppressed before use, and a certain dehumidifying function was secured, so that the polyethylene resin was sufficiently dehumidified during use. However, particulate defects are No. Occurs only in 5 films. This is no. Calcium oxide contained in Masterbatch 5 gradually absorbed moisture before use, and its surface became harder over time, so it was not compatible with polyethylene resin during film formation and part of it appeared on the film surface as an impurity. It is presumed that On the other hand, no. It can be seen that No. 6 had no particulate defects and did not absorb moisture enough to harden the surface of calcium oxide before use. From the above, it has been clarified that the moisture absorption of the chemically hygroscopic inorganic compound during storage can be more reliably suppressed by further containing the adsorptive inorganic compound in addition to the chemically hygroscopic inorganic compound.

Titanate coupling agent as a table surface modifier, aluminate-based coupling agent, providing a paraffin, said masterbatch No. No. 5 was replaced with stearic acid, and each prepared surface modifier was used to obtain No.5. 7-9 master batches were made. The composition is shown in Table 5.
Next, no. 5 and no. The master batches 7 to 9 were allowed to stand in a natural environment, and the appearance of the master batch was visually observed after 24 hours and 36 hours, and examined for changes in appearance. The results are shown in Table 5.

  Since none of the master batches changed in appearance after being left for 24 hours, in addition to stearic acid, all of titanate coupling agents, aluminate coupling agents and paraffins absorb moisture of inorganic compounds (calcium oxide) at room temperature. It was confirmed that If the master batch is left for a long time, No. Only 9 is whitened and other No. 5, 7 and 8 did not change. From this, it became clear that stearic acid, a titanate coupling agent, and an aluminate coupling agent have a greater effect of suppressing the hygroscopic function of inorganic compounds at room temperature than paraffin.

A master batch of the above Symbol No. In No. 9, the inorganic compound was changed to 40% by weight of calcium oxide and 10% by weight of zeolite. Ten master batches were made. Next, the obtained No. About 10 of the masterbatch, and left under the above SL as well as the natural environment, to observe the appearance of the master batch was visually after 36 hours, were examined for appearance changes. As a result, it was confirmed that there was no change in appearance after 36 hours.

  The master batch of No. 10 differs from the master batch of No. 9 only in that it contains not only a dehumidifier made of calcium oxide but also a dehumidifier made of zeolite as a dehumidifier. The appearance of the masterbatch after standing for 36 hours was whitened with No. 9, whereas No. 10 was not changed. This shows that the moisture absorption of calcium oxide is more reliably inhibited in the No. 10 master batch. In this way, the combined use of the chemically hygroscopic inorganic compound and the adsorptive inorganic compound inhibits the moisture absorption of the chemically hygroscopic inorganic compound for a longer time than the adsorption of the chemically hygroscopic inorganic compound with only the surface modifier. It was revealed that the master batch can be stored for a long time.

Claims (2)

A master batch that is mixed and molded with a plastic material when the plastic material is molded, and melts with the plastic material,
Containing a dehumidifying agent and a thermoplastic resin as a binder,
The dehumidifying agent improves the compatibility between the inorganic compound and the thermoplastic resin by covering the surface of the inorganic compound with a hygroscopic powder and the inorganic compound, and also has a hygroscopic function of the inorganic compound at room temperature. A surface modifier that suppresses and exerts the hygroscopic function of the inorganic compound during heating,
The inorganic compound Ri adsorbing inorganic compound der to moisture absorption by adsorbing a chemical hygroscopic inorganic compounds and moisture absorbs moisture by chemical reaction with water,
The chemically hygroscopic inorganic compound is calcium oxide,
The adsorptive inorganic compound is zeolite;
The surface modifier is at least one selected from the group consisting of titanate coupling agents, aluminate coupling agents, and stearic acids,
The proportion of the dehumidifying agent contained in the master batch is 20% by weight or more and 90% by weight or less.
A plastic dehumidification masterbatch that absorbs moisture contained in the plastic material during molding of the plastic material. A dehumidifying agent and a thermoplastic resin as a binder. The dehumidifying agent comprises a powder of an inorganic compound having hygroscopicity, and a surface of the inorganic compound covering the inorganic compound and the thermoplastic resin. And a surface modifier that improves the compatibility and suppresses the hygroscopic function of the inorganic compound at room temperature, and the inorganic compound absorbs a chemically hygroscopic inorganic compound that absorbs moisture by a chemical reaction with water and moisture. An adsorbing inorganic compound that absorbs moisture, the chemically hygroscopic inorganic compound is calcium oxide, the adsorbing inorganic compound is zeolite, and the surface modifier is a titanate coupling agent, an aluminate coupling agent, and It is at least one selected from the group consisting of stearic acids, and the proportion of the dehumidifying agent contained in the masterbatch is 20% by weight Add a master batch for plastic dehumidification of 90% by weight or less to the plastic material when molding the plastic material, and remove moisture in the plastic material by exerting the moisture absorbing function of the inorganic compound by heating during the molding To dehumidify plastic material.