JP2007260941A - Manufacturing method of paper compounded thermoplastic resin composition and paper pellet used therein - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the kneading productivity of plastic film laminated paper hard to be finely ground and the dispersibility of non-fibrillated cellulose fibers, to reduce heat generation in a kneading process and to further prevent yellowing in a manufacturing method of a paper compounded thermoplastic resin composition. <P>SOLUTION: The manufacturing method of the paper compounded thermoplastic resin composition containing pulp or ground old paper and a thermoplastic resin and compounded by kneading has a process for heating and kneading a mixture or composition, which contains the pulp or the ground old paper and the thermoplastic resin, in the presence of a cellulose fiber swelling agent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an environmentally friendly resin composition comprising a pulverized paper and one or both of a thermoplastic resin and a biodegradable resin. The present invention also relates to a production method for improving the productivity of the heat-kneading process and paper dispersion in producing an environmentally conscious resin composition, and reducing the burning coloring caused by kneading heat generation and the accompanying odor problem.

  As a molded body in consideration of environmental protection, a material made from a mixture of a thermoplastic resin and a material obtained by pulverizing pulp, waste paper, or the like is known. However, pulp and waste paper, etc., which are generally defibrated and secondarily pulverized from primary pulverization and pulverized, are bulky and difficult to handle, resulting in poor kneading productivity. In addition, when a highly pulverized pulp or used paper is blended in a high amount, the motor load of the kneading extruder is large and heat is likely to be generated, so that there is a problem that coloring and odor are generated due to burning.

  On the other hand, the method of recycling wet plastic film laminated paper as a papermaking raw material requires separation of the paper and film, and although the recovered fiber content is effectively used, the separated laminated film can be incinerated or landfilled. A method for reusing the entire laminated waste paper has not been put to practical use.

  In order to use this plastic film-laminated waste paper as an environmentally friendly resin composition, if a coarsely pulverized product with a 3 mm hole diameter pass that can be pulverized relatively easily is used, the undispersed material of the coarsely crushed waste paper is exposed on the surface of the molded body. There is a problem of detracting from aesthetics.

  As a method for solving the above problems, a method for producing a composition (for example, see Patent Document 1) comprising a defibrated waste paper and a dispersibility improver (for example, see Patent Document 1) or a plastic film laminated paper finely cut product (for example, see Patent Document 2). Etc.) have been proposed.

Japanese Patent No. 3007880 JP 2004-58254 A

  However, in the above method, a binder such as a low melting point resin must be mixed in advance in order to reduce the bulk of the defibrated waste paper. Furthermore, dry fine pulverization for finely pulverizing waste paper is required as a pretreatment. In particular, for dry fine pulverization, a special pulverizer for increasing the number of pulverizations and the pulverization time is required.

  However, when crushing paper laminated on both sides with a plastic film such as polyethylene film, the polyethylene film laminated with heat generated by crushing melts and adheres to the crusher screen, so the crushing particle size is increased to the extent that the screen does not clog. The method has been implemented. The obtained highly blended resin composition of the pulverized plastic film laminated paper having a large pulverized particle size has a large motor load on the kneading extruder and is likely to be burned due to kneading heat generation.

  As a countermeasure against this, it is usual to maintain whiteness by blending titanium dioxide or the like. Although this measure can reduce yellowing due to burning on the appearance to a level that is hardly noticed, when water is applied to the molded product, yellowing due to burning occurs on the applied water or molded product.

  The mechanism is not necessarily clear, but when the present inventors investigated, it occurred when the colored components generated by the high temperature during the kneading and molding process were extracted into the water layer and used. It was found to be a colored component derived from the paper and kneading conditions. When such a phenomenon occurs, the quality of the molded product is remarkably impaired. Therefore, there has been a demand for a resin composition that does not turn yellow even when water is applied. However, there is no literature on the yellowing phenomenon, especially the yellowing phenomenon involving water, in the paper-containing thermoplastic resin composition.

  Accordingly, an object of the present invention is to improve the kneading productivity of plastic film laminated paper that is difficult to pulverize, the dispersibility of cellulose fibers that have not been defibrated, and the heat of paper blending that can reduce heat generation in the kneading process. It is providing the manufacturing method of a plastic resin composition. And by this manufacturing method, especially the yellowing which water intervenes with respect to the yellowing which arises in the heat-kneading and shaping | molding process of the resin composition containing paper was reduced remarkably, and it was generated by the kneading heat_generation | fever. An object of the present invention is to provide a molded article of an environmentally friendly resin composition in which a coloring component is decolorized. Furthermore, it aims at providing the paper pellet suitable for this manufacturing method.

  As a result of proceeding the kneading of various types of used paper that has been coarsely pulverized, defibrated, or finely pulverized, the present inventors have found paper pellets with good resin kneading productivity. As a second invention, the present inventors have found a method for producing an environmentally conscious resin composition that can knead in the presence of a cellulose fiber swelling agent to defibrate paper components and round fibers, and at the same time reduce burns due to kneading heat generation. .

  That is, the paper pellet according to the present invention is a cylindrical pellet obtained by forming a pulverized plastic film laminated paper with a non-screw type granulator, and the cellulose fiber swelling agent is 2 to 30 mass with respect to 100 mass parts of the cylindrical pellet. It is characterized by partial absorption.

  A method for producing a paper-blended thermoplastic resin composition according to the present invention includes a pulp or crushed waste paper and a thermoplastic resin, and a method for producing a paper-blended thermoplastic resin composition combined by kneading. It has a step of heat-kneading a mixture or composition containing the pulverized waste paper and the thermoplastic resin in the presence of a cellulose fiber swelling agent.

  A method for producing a paper-blended thermoplastic resin composition according to the present invention includes a paper pellet according to the present invention, a mixture containing pulp or crushed waste paper and a thermoplastic resin, a composition comprising pulp or crushed waste paper and a thermoplastic resin, Alternatively, the cellulose fiber swelling agent 2 to 300 is used with respect to any one of the cylindrical pellets obtained by melting the mixture or the composition with a high-speed mixer and molding the mixture with a non-screw type granulator, or 100 parts by mass of the mixture. And a step of adjusting a kneading mixture to which 10 parts by mass and 10 to 200 parts by mass of a thermoplastic resin are added, and a step of heating and kneading the kneading mixture in the presence of the cellulose fiber swelling agent. .

  The method for producing a paper-blended thermoplastic resin composition according to the present invention includes a step of adjusting a kneading mixture in which at least 10 to 200 parts by mass of a thermoplastic resin is added to 100 parts by mass of the paper pellets according to the present invention; And kneading the mixture for kneading in the presence of a cellulose fiber swelling agent absorbed in the paper pellets.

  The method for producing a paper-containing thermoplastic resin composition according to the present invention includes a mixture containing pulp or crushed waste paper and a thermoplastic resin, a composition containing pulp or crushed waste paper and a thermoplastic resin, or the mixture or the composition Kneading by adding at least 2 to 300 parts by weight of a cellulose fiber swelling agent to 100 parts by weight of any one of cylindrical pellets formed by resin melting with a high-speed mixer and molding with a non-screw type granulator And a step of heat-kneading the kneading mixture in the presence of the cellulose fiber swelling agent.

  In the method for producing a paper-blended thermoplastic resin composition according to the present invention, in the step of heating and kneading, the paper pellets, the columnar pellets, or both of them are unraveled. Since the cellulose fiber swelling agent was present when heated and kneaded, the pellets were unwound.

  In the method for producing a paper-blended thermoplastic resin composition according to the present invention, the heat-kneading step includes proceeding with the defibration of the paper contained in the kneading mixture. Since the cellulose fiber swelling agent is present when heated and kneaded, the paper is defibrated and the dispersibility of the cellulose fibers is improved.

  In the method for producing a paper-blended thermoplastic resin composition according to the present invention, in the heating and kneading step, the fibrillated cellulose fibers are rounded. Since the cellulose fiber swelling agent is present when heated and kneaded, the fibrillated cellulose fibers are rounded. Thereby, the intense roundness of fibers can be suppressed and the fall of the beauty | look of the surface of a molded object can be suppressed.

  In the method for producing a paper-containing thermoplastic resin composition according to the present invention, the pulp or the crushed waste paper is a finely pulverized paper, a defibrated paper, a coarsely pulverized paper having a diameter of 0.5 mm to 3 mm, A coarsely pulverized plastic film laminated paper having passed through a hole having a diameter of 0.5 mm to 3 mm, a wet pulp having a moisture content of 40 to 65% by mass, a pulp sheet for papermaking having a moisture content of 5 to 50% by mass, or a mixture thereof. Including.

  In the method for producing a paper-containing thermoplastic resin composition according to the present invention, the cellulose fiber swelling agent is preferably water. Water easily penetrates into paper, wets the paper, has a defibrating effect, and can improve the dispersibility of cellulose fibers. And subsequent separation is also easy.

  In the method for producing a paper-blended thermoplastic resin composition according to the present invention, it is preferable to add a surfactant and / or a bleaching agent in the step of preparing the kneading mixture or the step of heating and kneading. Since the interfiber bonding of the cellulose fibers is manifested together with the scattering of the cellulose fiber swelling agent such as water during kneading, this can be suppressed by adding a surfactant. Further, yellowing can be prevented by adding a bleaching agent.

  In the method for producing a paper-containing thermoplastic resin composition according to the present invention, it is preferable to further include a step of bringing the paper-containing thermoplastic resin composition obtained through the heating and kneading step into contact with a bleaching agent. In a composite material obtained by heating and kneading paper and a thermoplastic resin, the composite material and a bleaching agent can be brought into contact with each other to decolorize the coloring component of the composite material.

  In the method for producing a paper-blended thermoplastic resin composition according to the present invention, the bleaching agent is preferably a borohydride compound. It is inexpensive and highly effective in preventing yellowing.

  According to the present invention, in the method for producing a paper-blended thermoplastic resin composition, the kneading productivity of a plastic film laminated paper that is difficult to pulverize and the dispersibility of cellulose fibers that have not been defibrated are improved. It is possible to reduce heat generation. Here, paper pellets suitable for this manufacturing method can be provided. And by this manufacturing method, especially the yellowing which water intervenes with respect to the yellowing which arises in the heat-kneading and shaping | molding process of the resin composition containing paper was reduced remarkably, and it was generated by the kneading heat_generation | fever. It is possible to provide a molded product of an environmentally friendly resin composition having a high commercial value in which the coloring component is decolorized. The hue of the resin composition can be improved near normal temperature and is simple and efficient. Furthermore, the range of used paper can be expanded, which can contribute to the reduction of environmental load from the viewpoint of effective use of resources.

  Hereinafter, the present invention will be described, but the present invention is not construed as being limited to these embodiments. The method for producing a paper-blended thermoplastic resin composition according to the present embodiment includes pulp or crushed waste paper and a thermoplastic resin, and a method for producing a paper-blended thermoplastic resin composition combined by kneading. A step of heating and kneading a mixture or composition containing pulverized waste paper and a thermoplastic resin in the presence of a cellulose fiber swelling agent. By carrying out heat kneading in the presence of a cellulose fiber swelling agent, kneading productivity and dispersibility of cellulose fibers can be improved, and heat generation in the kneading step can be reduced.

  More specifically, the manufacturing method of the paper-blended thermoplastic resin composition according to the present embodiment is (1) paper pellets according to the present embodiment, or (2) pulp or crushed waste paper and heat as the first mode. A mixture containing a plastic resin, or (3) a composition containing pulp or crushed waste paper and a thermoplastic resin, or (4) a mixture of (2) or a composition of (3) is melted with a high-speed mixer. Cellulose fiber swelling agent 2 to 300 parts by mass and thermoplastic resin 10 to 100 parts by mass of any one of cylindrical pellets molded by a non-screw type granulator or (1) to (4). A step of adjusting a kneading mixture to which 200 parts by mass are added, and a step of heat-kneading the kneading mixture in the presence of the cellulose fiber swelling agent. Here, the paper pellet according to the present embodiment is composed of a cylindrical pellet formed by pulverized plastic film laminated paper with a non-screw type granulator, and a cellulose fiber swelling agent absorbed in the cylindrical pellet. The cellulose fiber swelling agent is absorbed by 2 to 30 parts by mass with respect to 100 parts by mass of the cylindrical pellet.

  The manufacturing method of the second form includes (1) a step of adjusting a kneading mixture in which at least 10 to 200 parts by mass of a thermoplastic resin are added to 100 parts by mass of the paper pellet according to the present embodiment, and the kneading mixture. Heating and kneading in the presence of a cellulose fiber swelling agent absorbed in the paper pellets.

  Moreover, the manufacturing method of 3rd form is the composition containing (2) pulp or ground waste paper, and a thermoplastic resin, (3) The composition containing pulp or ground waste paper, and a thermoplastic resin, or (4) (2 ) Or 100 parts by mass of the mixture of (3) or the composition of (3) by resin melting with a high-speed mixer and molding with a non-screw type granulator or one of the cylindrical pellets of (2) to (4) And a step of preparing a kneading mixture to which at least 2 to 300 parts by mass of a cellulose fiber swelling agent is added, and a step of heating and kneading the kneading mixture in the presence of the cellulose fiber swelling agent.

  The manufacturing methods of the first to third forms are specific forms, but are not limited to these, and are included in the present embodiment as long as they have a step of heat-kneading in the presence of a cellulose fiber swelling agent. . More specific description will be given below.

  Pulp or crushed waste paper is a raw material for cellulose fibers to be included in a paper-containing thermoplastic resin composition. Examples of cellulose fibers include alkali treatment of wood pulp, refiner ground pulp (RGP), waste paper-derived pulp, or wood pulp. Then, there are mechanically shredded alpha fiber flocs, cotton linters obtained from cotton seeds, cotton flocs, human silk flocks shredded from human silk, or carboxymethylcellulose and methylcellulose, which are fiber derivatives.

  In this embodiment, pulp or crushed waste paper is (a) a finely pulverized material of paper, (b) a defibrated material of paper, (c) a coarsely pulverized paper having passed through a hole having a diameter of 0.5 mm to 3 mm, (d) Coarsely pulverized plastic film laminated paper having passed through a hole having a diameter of 0.5 mm to 3 mm, (e) wet pulp having a moisture content of 40 to 65% by mass, or (f) a pulp sheet for papermaking having a moisture content of 5 to 50% by mass or ( g) A mixture of (a) to (f) is preferred.

  These (a) finely pulverized paper and (b) defibrated material mainly composed of these cellulose fibers are, for example, scraps generated when the size of a formed paper once adjusted, office automation waste paper (OA waste paper) It is assumed that newspaper waste paper, cardboard waste paper, or the like is usually pulverized to about 20 to 200 mesh passes. Further, (c) coarsely pulverized paper having passed through a hole having a diameter of 0.5 mm to 3 mm and (d) coarsely pulverized plastic film laminated paper having passed through a hole having a diameter of 0.5 mm to 3 mm are the above-mentioned formed paper, polyolefin film 15 There are photographic printing paper and milk carton trimming waste laminated with ~ 50 μm. Further, (e) wet pulp having a moisture content of 40 to 65% by mass is a disaggregated dehydrated pulp obtained in a papermaking process. Examples of the papermaking pulp sheet having a water content of 5 to 50% by weight include commercially available softwood bleached kraft pulp, hardwood bleached kraft pulp, and softwood unbleached kraft pulp sheet.

  The paper used in the present embodiment is better as the whiteness is higher, and is usually ISO whiteness (JIS P 8148: 2001 “Paper, paperboard and pulp—Method of measuring ISO whiteness (diffuse blue light reflectance)”). It is 75% or more, more preferably ISO whiteness is 80% or more. When the ISO whiteness is lower than 75%, the degree of yellowing increases. For example, newspaper waste paper and corrugated waste paper using mechanical pulp and unbleached pulp are likely to cause yellowing due to heat, and even if a predetermined effect is obtained, the use of a bleaching agent may significantly increase and increase costs. is there.

  More desirable paper in this embodiment is milk carton trimming waste of plastic film laminated paper that has high whiteness and is not easily pulverized, and can be effectively used as an environmentally friendly resin composition. However, the pulverized material that has passed through the 1 mm diameter round hole screen is bulky with an apparent specific gravity of 0.1 or less, and the kneading workability is very poor.

  In order to improve this problem, the bulk of the bulky pulverized product is reduced. Specifically, the bulk reduction is performed as the paper pellet according to the present embodiment. For example, it is formed into a cylindrical pellet having a diameter of 3 to 10 mm, a length of 3 mm to 10 mm, and an apparent specific gravity of 0.3 to 0.7 with a non-screw type granulator. The crushed milk carton trimming waste can be put into a non-screw type granulator as it is because the plastic film is uniformly dispersed in the pulverized product. The diameter, length, and apparent specific gravity of the cylindrical pellet can be adjusted by the die specification and the cutter position.

  Preferably, in order to maintain the shape even when the following cellulose fiber swelling agent is used, it is desirable to mold the material with an apparent specific gravity of 0.5 or more. The cellulose fiber swelling agent is easily adsorbed on the cylindrical pellet having a high paper ratio, and makes the paper pellet unwound and the cellulose fiber is well dispersed. When the apparent specific gravity of the cylindrical pellet is less than 0.3, the kneading workability such as the transferability of the cylindrical pellet or paper pellet is deteriorated. When the apparent specific gravity is larger than 0.7, the power consumption of the non-screw type granulator is exceeded. It tends to cause load and poor dispersion of cellulose fibers.

  In forming the cylindrical pellet, a thermoplastic resin may be added. For example, the milk carton trimming waste already contains a thermoplastic resin such as polyethylene, but can be applied to increase the content of the thermoplastic resin. Moreover, when forming a cylindrical pellet, you may add a cellulose fiber swelling agent suitably.

  The paper pellet according to the present embodiment is obtained by absorbing the cellulose fiber swelling agent in the columnar pellet formed in this way. Here, the cellulose fiber swelling agent is absorbed 2 to 30 parts by mass, preferably 5 to 20 parts by mass with respect to 100 parts by mass of the cylindrical pellet. When the addition amount of the cellulose fiber swelling agent is less than 2 parts by mass, it is difficult for the paper pellets to be unraveled and the dispersion of the cellulose fibers to proceed, and when it exceeds 30 parts by mass, the paper pellets are easily released, and the meterability, transportability, etc. Deteriorating kneading workability.

  In producing the paper-containing thermoplastic resin composition, the cellulose fiber swelling agent may be absorbed in advance in (1) the paper pellet according to the present embodiment, but (2) pulp or crushed waste paper and heat. A mixture containing a plastic resin, or (3) a composition containing pulp or crushed waste paper and a thermoplastic resin, or (4) a mixture of (2) or a composition of (3) is melted with a high-speed mixer. When any of the cylindrical pellets molded with a non-screw type granulator is used as a raw material for cellulose fibers, it may be added to these. (1) to (4) are used alone, but (1) paper pellets according to this embodiment, a mixture of (2), a composition of (3), and a cylindrical pellet of (4) are appropriately combined. May be used. For example, (1) and (2), (1) and (3), (1) and (4), (2) and (3), (2) and (4), or (3) and (4) Two combinations or (1) and (2) and (3), (1) and (2) and (4), (1) and (3) and (4), (2) and (3) And (4), or (1), (2), (3), and (4).

  As the cellulose fiber swelling agent, water that permeates and wets paper and has a defibrating effect may be obtained from the subsequent separability. Water as a cellulose fiber swelling agent can effectively loosen the interfiber bonds of cellulose fibers and improve the dispersibility of the cellulose fibers in a high temperature, high pressure or high temperature / high pressure atmosphere of the kneading step. Here, the mixing ratio of water which is a cellulose fiber swelling agent is (1) paper pellets according to the present embodiment, or (2) a mixture containing pulp or crushed waste paper and a thermoplastic resin, or (3) pulp. Alternatively, a composition containing crushed waste paper and a thermoplastic resin, or cylindrical pellets obtained by melting the mixture of (4) and (2) or the composition of (3) with a high-speed mixer and molding with a non-screw type granulator, It is in the range of 2-300 mass parts with respect to 100 mass parts of any 1 type of these, or the mixture of (1)-(4). In the case where paper defibration using stirring shearing force such as a high-speed stirring mixer is advanced, the amount is 50 to 300 parts by mass, preferably 100 to 200 parts by mass. In addition, it is preferable to use a twin screw extruder or the like to disentangle the cellulose fibers from the unraveling of the paper pellets or the cylindrical pellets or both, further round the cellulose fibers, and facilitate water removal. Is preferably 2 to 20 parts by mass. The motor power load of the extruder tends to be reduced from 2 parts by mass or more of water, which is a cellulose fiber swelling agent, for unknown reasons. When the amount exceeds 300 parts by mass of water, although the paper dispersion effect is large, moisture tends to remain, and a post-process for removing moisture is required. This is not limited as long as there is a step of forming pellets by extrusion again.

  In addition, when the cellulose fiber length is long or the paper blending ratio is high, the fibers are entangled and easily rounded after defibration. When the roundness of the fibers becomes intense, it is exposed on the surface of the molded body and the aesthetic appearance is impaired. In order to prevent this intense rounding of the fibers, the following interfiber bonding inhibitor of cellulose fibers is used. When the paper is defibrated with a high-speed agitating mixer or the like, a surfactant or the like is effective as an inhibitor because the interfiber bonding of cellulose fibers is manifested along with the scattering of moisture. The surfactant is added in the step of adjusting the kneading mixture or the step of heat kneading.

  Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and higher fatty acids such as stearic acid, calcium stearate, magnesium, zinc salts, and salts thereof. And higher fatty acids such as stearyl alcohol, glycerin monostearate and polyethylene glycol, higher polyhydric alcohols, and various fatty acid esters such as polyoxyethylene sorbitan monostearate. As other inhibitors, powder low density polyethylene, carboxylic acid-modified polyethylene, carboxylic acid-modified silicone oil, higher fatty acid esters and the like are also preferable. One type of these interfiber bond inhibitors may be used, or two or more types may be used in combination. The blending amount includes (1) paper pellets according to the present embodiment, or (2) a mixture containing pulp or crushed waste paper and a thermoplastic resin, or (3) pulp or crushed waste paper and a thermoplastic resin. Any one of the composition, (4) (2) mixture or (3) cylindrical pellet formed by resin melting with a high speed mixer and molding with a non-screw type granulator or (1) to It is selected in the range of 0.3 to 100 parts by mass with respect to 100 parts by mass of the mixture of (4).

  In the step of adjusting the kneading mixture or the step of heat-kneading, a bleaching agent may be added. Yellowing of the paper-containing thermoplastic resin composition can be prevented. As bleaching agents, lithium borohydride, sodium borohydride (hereinafter abbreviated as “SBH”), potassium borohydride, rubidium borohydride, cesium borohydride, beryllium borohydride, magnesium borohydride Borohydride compounds such as calcium borohydride, tetrabutylammonium borohydride, and the like can be mentioned, but SBH is preferable because of its availability. SBH is used in the form of powder or alkaline aqueous solution.

  The addition ratio of the borohydride compound is (1) paper pellets according to this embodiment, or (2) a mixture containing pulp or crushed waste paper and thermoplastic resin, or (3) pulp or crushed waste paper and thermoplastic. Any one of a composition containing a resin, or a cylindrical pellet obtained by melting the resin of (4) (2) or the composition of (3) with a high-speed mixer and molding with a non-screw type granulator, or It exists in the range of 0.01-2.0 mass parts with respect to 100 mass parts of the mixture of (1)-(4). More preferably, it is 0.1-1.0 mass part. When the addition rate is lower than 0.01 parts by mass, the yellowing prevention effect is insufficient. When the addition rate is more than 2.0 parts by mass, an excess of unreacted borohydride compound remains in the resin composition. The borohydride compound absorbs moisture and precipitates a crystalline product of a strongly alkaline metaboric acid compound. In injection molding, molding tends to become unstable due to foaming. When the paper-containing thermoplastic resin composition has already formed a colored product, it is necessary to determine an appropriate addition rate in view of the degree of yellowing. Appropriate addition rates are tested using the paper-blended thermoplastic resin composition itself, and further assuming heat applied in the heat-kneading and molding steps.

  In the present embodiment, when the borohydride compound is added prior to pelletization in the kneading step, the reaction can be promoted by utilizing heat during kneading and is originally present in the paper, or is pulverized and kneaded. It seems that the formation prevention and the removal effect of the coloring component generated by the heat of the process act simultaneously. Further, by leaving the borohydride compound, the decoloring action continues and the colored components can be eliminated or reduced. As another addition means, you may further provide the process (henceforth a "post process") which makes the paper compounding thermoplastic resin composition obtained through the process of heat-kneading and a bleaching agent contact. For example, a method of using a master batch of a borohydride compound in a molding process such as injection molding or extrusion molding, or a method of mixing the paper-blended thermoplastic resin composition of the present embodiment can also be mentioned.

  Note that not only one of the surfactant and the bleaching agent may be added, but both may be added.

  Kneading / molding of borohydride compound and coloring component and reaction in the post-process does not cause alkaline elution of resin and paper or alkali burning (darkening) of paper from acidic region where borohydride compound is not easily decomposed. It is necessary to adjust the pH within the range. The pH is preferably in the acidic range above 5 to the above alkaline range, for example, pH 11 or less. When powder of borohydride is used in the kneading process, depending on conditions, it is affected by acidic components due to thermal decomposition of the paper. Therefore, prior to the addition of borohydride compound, sodium hydroxide, calcium hydroxide, calcium oxide It is preferable to adjust with a pH adjuster such as calcium carbonate. When a sodium hydroxide aqueous solution of a borohydride compound is used, the temperature from kneading to pelletization becomes 120 ° C. or higher, which causes darkening of the paper-blended thermoplastic resin composition with a high concentration sodium hydroxide aqueous solution. For this reason, the adjustment of pH is particularly important. Next, in order to decolorize the coloring component of the paper-containing thermoplastic resin composition and improve the hue in the subsequent step, the paper-containing thermoplastic resin composition containing the borohydride compound and the molded product contain water or water. It can be done by adding to and contacting the mixture. Or you may use the water | moisture content contained in a paper mixing thermoplastic resin composition and a molding, or adsorption water of environmental atmosphere. Of course, the paper-containing thermoplastic resin composition and the molded article can be used by immersing in water or an aqueous mixed solution containing a borohydride compound. Although reaction temperature can be set suitably, in the case of water, it is preferable that it is 5-50 degreeC. More preferably, it is 10-35 degreeC.

  As the thermoplastic resin used in the present embodiment, polyethylene resin, polypropylene resin, polystyrene resin, acrylonitrile / butadiene / styrene resin (ABS), acrylonitrile / styrene resin (AS), urethane resin, polyester resin, polycarbonate resin, etc. Various resins such as polylactic acid, polybutylene succinate, polyvinyl alcohol, and cellulose acetate can be used as the resin and biodegradable resin. Among these resins, in order to suppress thermal discoloration of the pulverized paper, polypropylene resins and polyethylene resins having a melting point at a relatively low temperature are more preferable because they are inexpensive and suitable for recycling. These resins may be a homopolymer or a copolymer, may be a pulverized product or a recycled product of a used molded product, and may be a single polymer or a mixture.

  In order to obtain an environment-friendly type, the mixing ratio of the pulverized paper and the thermoplastic resin is blended so that the thermoplastic resin is less than 50% by mass, for example, 49% by mass or less of the total mass of both. A preferable blending ratio is a range of pulverized paper / thermoplastic resin = 51/49 mass% to 70/30 mass%. Fluidity improver (maleic anhydride modified polypropylene resin, polyethylene wax, rosin ester, organic peroxide, etc.), antioxidant (hindered phenol antioxidant, etc.), pigment (titanium oxide, calcium carbonate) as required Etc.) may be added as long as the effect of the present invention is not affected.

  In the case of a resin composition containing a pulverized paper and a biodegradable resin as main components, since both are biodegradable, there is no blending ratio for making an environmental type. The blending ratio is determined by the moldability and the quality requirements of the molded product. Usually, the pulverized paper / biodegradable resin is in the range of 10/90 mass% to 90/10 mass%. Moreover, you may use the auxiliary | assistant similar to the above and a white filler suitably.

  In the method for producing a paper-blended thermoplastic resin composition according to this embodiment, the kneading mixture to be kneaded is, for example, (A) paper pellets, pulp or crushed waste paper and thermoplastic resin according to this embodiment. Any one of a mixture containing pulp, a composition containing pulp or crushed waste paper and a thermoplastic resin, or a cylindrical pellet obtained by melting the mixture or the composition with a high-speed mixer and molding it with a non-screw type granulator, or When it is a mixture of these mixtures, cellulose fiber swelling agent and thermoplastic resin, (B) When it is a mixture of paper pellets and thermoplastic resin according to this embodiment, (C) pulp or crushed waste paper and heat A mixture containing a plastic resin, a composition containing pulp or crushed waste paper and a thermoplastic resin, or a high-speed mixer using the mixture or the composition If a mixture of the resin melt either one or a mixture of these cylindrical pellets were molded in a non-screw-type granulator and cellulosic fibers swelling agent. When preparing these kneading mixtures, for example, not only when mixing but also when forming cylindrical pellets, various auxiliary agents such as surfactants, bleaches, fluidity improvers, antioxidants, pigments, etc. Can be added. Further, it may be added when kneading.

  In addition, in the step of preparing the intermediate mixture that has been pre-kneaded by pre-mixing the mixture for kneading in advance, in the step of heating and kneading, as a step of performing only heating kneading without adding a new compound good.

  A conventionally known method can be used as the method for producing the paper-blended thermoplastic resin composition according to this embodiment, and a kneading step comprising a high-speed stirring mixer, a twin screw extruder, or a combination thereof can be used. For example, one or both of the pulverized paper and the paper pellet, the cellulose fiber swelling agent, one or both of the surfactant and the bleaching agent, and the thermoplastic resin are adjusted to a predetermined ratio. After measurement, the mixture is uniformly mixed by a kneading means such as a high-speed stirring mixer. Alternatively, kneading is performed up to the melting temperature of the thermoplastic resin. Alternatively, a composition containing at least one of a cellulose fiber swelling agent, a surfactant, and a bleaching agent is continuously fed to one or both of a paper pulverized material and a paper pellet to the feeder of the extruder. And can be pelletized. The continuous stable supply to the extruder is a paper according to the present embodiment in the form of a column having a diameter of 3 mm to 10 mm, a length of 3 mm to 10 mm, and an apparent specific gravity of 0.3 to 0.7, particularly in a non-screw type granulator. This can be achieved by forming into pellets. Moreover, since the paper pellet according to this embodiment of the columnar shape has water absorption properties and easily retains the cellulose fiber swelling agent, the cellulose fiber swelling agent can be added in advance. Although the temperature at the time of heat-kneading changes suitably with resin, it is set to 120-180 degreeC, for example.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not limited to these Examples. The evaluation was performed by the following method.

(Dispersibility of cellulose fiber)
The appearance of the multipurpose test piece (JIS K 7139: 1996 “Plastic-Multipurpose Test Specimen”), which is an injection-molded product using pellets made of the obtained paper-containing thermoplastic resin composition, was visually observed, and an aggregate of cellulose fibers. It evaluated from the uniformity by the presence or absence.
◯: There is no rounding and aggregation of cellulose fibers and it is uniform.
Δ: Slight rounding of cellulose fibers and cellulose fiber aggregates of less than 1 mm ² , which are practical.
X: There are rounded cellulose fibers and cellulose fiber aggregates of 1 mm ² or more, which are not practical.
Injection molding machine: F85 manufactured by Crooker.
Mold temperature: 40 ° C.
Barrel set temperature: Nozzle 180 ° C, front 175 ° C, central 170 ° C, rear 160 ° C.
Injection / holding time: 18 seconds.

(Water dissolution test and yellowing evaluation method)
Pellets made of the obtained paper-blended thermoplastic resin composition and distilled water were placed in a polyethylene bag, and air was discharged as much as possible and held under the conditions of each example. Thereafter, the degree of coloration of the water layer was evaluated visually. The visual evaluation was determined according to the following criteria. Or the light absorbency in wavelength 400nm was measured about the filtered water layer using the spectrophotometer (the Shimadzu Corporation make, UV-1650PC). Further, the hue of pellets made of a paper-containing thermoplastic resin composition (Minolta (currently Konica Minolta Holdings) color difference meter CR-300, light source D ₆₅ ) and ISO whiteness (JIS P 8148: 2001 “paper, paperboard and pulp-ISO Measuring method of whiteness (diffuse blue light reflectance) ").
A: Colorless and practical.
○: Almost colorless and practical.
Δ: Light yellow and practical.
X: Yellow and not practical.

Example 1
Milk carton trimming waste (basis weight 357 g / m ² , paper ISO whiteness 80%, low density polyethylene film 17.9 μm surface and backside 29.2 μm laminate, low density polyethylene: Mirason M-16P (Mitsui Chemicals) MFR (Melt Flow Rate) = 3.7) Opening 1 mm square hole screen pulverized material (including non-defibrated paper having an apparent specific gravity of 0.07, a moisture content of 4 mass%, and 1 mm ² ). The pellets were supplied to a granulator (disc pelleter F-5, manufactured by Dalton) to obtain cylindrical pellets having a diameter of 3 mm, a length of 2 to 5 mm, a moisture content of 3 mass%, and an apparent specific gravity of 0.53. 10 parts by mass of water was absorbed as a cellulose fiber swelling agent with respect to 100 parts by mass of the cylindrical pellets to obtain paper pellets. To 100 parts by mass of the paper pellets, 60 parts by mass of polypropylene resin (BC05B, manufactured by Nippon Polypro) and 3 parts by mass of maleic anhydride-modified polypropylene resin (Yumex 1010, manufactured by San Nopco) as a fluidity improver were mixed, The mixture was supplied to a twin-screw extruder having a degassing step and kneaded into pellets to obtain pellets made of a paper-containing thermoplastic resin composition. The twin-screw extruder was under the following conditions, and the resin temperature in the extrusion pelletizing step was 150 ° C. The motor power load was stable. No white smoke and pellets adhered to the exit of the extruder. In the water elution test, 70 g of pellets made of a paper-containing thermoplastic resin composition and 20 ml of distilled water are put in a polyethylene bag, air is discharged as much as possible and kept at 40 ° C. for 2 days, and then the degree of coloring of the water layer is evaluated visually. did. The results are shown in Table 1.
(Conditions for twin screw extruder)
Twin screw extruder: TEM44 manufactured by Toshiba Machine.
L / D (ratio of screw length to screw diameter) = 28.
Cylinder temperature: C1 and C2 are 160 ° C, C3 to C7 are 120 ° C, and extrusion is 150 ° C.
Screw rotation speed: 150 r. p. m. .
Extrusion speed: 100 kg / hr.
Degassing: There is vacuum degassing.
Pelletization: Hot cut method.

(Example 2)
As a fluidity improver, 3 parts by mass of polyethylene wax (Excellex 30200B manufactured by Mitsui Chemicals) and anhydrous are used for 100 parts by mass (in terms of absolute dry mass) of the same kind of crushed milk carton trimming waste as used in Example 1 3 parts by weight of maleic acid-modified polypropylene resin (Yumex 1010 manufactured by San Nopco), 6 parts by weight of titanium dioxide (Taipeke A-220, manufactured by Ishihara Sangyo) as a pigment, and zinc stearate (SZ-2000, manufactured by Sakai Chemical Industry) as a surfactant 1 part by mass was heated and mixed to 125 ° C. with a high-speed stirring mixer (Henschel mixer FM20, manufactured by Mitsui Mine). Next, a cylindrical pellet having a diameter of 3 mm, a length of 5 mm, a water content of 1% by mass, and an apparent specific gravity of 0.56 was obtained using a non-screw type granulator. With respect to 100 parts by mass of the cylindrical pellet, 10 parts by mass of water was absorbed as a cellulose fiber swelling agent. Further, 71 parts by mass of a polypropylene resin (BC05B, manufactured by Nippon Polypro) was added to 100 parts by mass of the cylindrical pellet that had absorbed this water to obtain a mixture for kneading. Subsequently, it supplied to the twin-screw extruder which has the same deaeration process as Example 1, kneaded and pelletized, and the pellet which consists of a paper mixing | blending thermoplastic resin composition was obtained. The results are shown in Table 1.

(Example 3)
In Example 2, instead of adding polyethylene wax, 3 parts by mass of rosin ester (Superester A-100, manufactured by Arakawa Chemical Industries), which is a fluidity improver, was added and heated to 145 ° C. with a high-speed stirring mixer. Except for the above, pellets made of a paper-containing thermoplastic resin composition were obtained in the same manner. The results are shown in Table 1.

Example 4
100 mass parts of water as a cellulose fiber swelling agent and a surfactant (Evan 450, No. 1) with respect to 100 mass parts (absolute dry weight conversion) of 3 mm square hole screen-passed crushed fine paper-based waste paper (ISO whiteness 80%) 0.5 parts by weight, manufactured by Ichi Kogyo Seiyaku Co., Ltd., 95 parts by weight of polypropylene resin (BC05B, manufactured by Nippon Polypro), 3 parts by weight of maleic anhydride-modified polypropylene resin (Yumex 1010, manufactured by San Nopco) as a fluidity improver, and titanium dioxide as a pigment (Taipeke A-220, manufactured by Ishihara Sangyo Co., Ltd.) 6 parts by mass of paper is defibrated with a high-speed stirring mixer (Henschel mixer FM20, manufactured by Mitsui Mine), and then heated to 180 ° C to melt the resin. A cylindrical pellet having a water content of 0.3 mass% and an apparent specific gravity of 0.50 was obtained using a granulator. 10 parts by mass of water and 0.1 part by mass of SBH were mixed as a cellulose fiber swelling agent with respect to 100 parts by mass of this cylindrical pellet to obtain a mixture for kneading. This kneading mixture was supplied to a twin-screw extruder having the same degassing step as in Example 1 and kneaded into pellets to obtain pellets made of a paper-blended thermoplastic resin composition. The results are shown in Table 1.

(Example 5)
Except for 100 parts by mass of the columnar pellets of Example 4, 5 parts by mass of water as a cellulose fiber swelling agent and 0.5 parts by mass of SBH powder (Morton International) as a bleaching agent were the same as in Example 4. A pellet made of a paper-containing thermoplastic resin composition was obtained. The results are shown in Table 1.

(Example 6)
100 parts by weight of 100-mesh-pass crushed fine paper-based waste paper (ISO whiteness 80%) (converted to absolute dry weight), 90 parts by weight of polypropylene resin (BC05B, manufactured by Nippon Polypro), maleic anhydride-modified polypropylene as a fluidity improver 5 parts by mass of resin (Yumex 1010, manufactured by San Nopco), 6 parts by mass of titanium dioxide (Typaque A-220, manufactured by Ishihara Sangyo) as a pigment, and 1 part by mass of calcium hydroxide (reagent grade 1, Wako Pure Chemical Industries) as a pH adjuster Were mixed to 170 ° C. with a high-speed stirring mixer. Thereafter, 0.5 parts by mass of SBH powder (Morton International) as a bleaching agent was added and mixed uniformly, and then with a non-screw type granulator, the diameter was 3 mm, the length was 5 mm, the water content was 0.5 mass%, and the apparent specific gravity was 0. .53 cylindrical pellets were obtained. Next, 5 parts by mass of water was absorbed as a cellulose fiber swelling agent to obtain a mixture for kneading. This kneading mixture was supplied to a twin-screw extruder having the same degassing step as in Example 1, and pellets made of a paper-blended thermoplastic resin composition were obtained from kneading pelletization. The results are shown in Table 1.

(Example 7)
A pulp sheet (moisture content of 50%) of hardwood bleached kraft pulp (LBKP) was used instead of the fine paper waste paper of Example 6 (ISO whiteness 80%) 100 mesh pass pulverized product. The water content of the pulp sheet was substituted as the cellulose fiber swelling agent. At this time, it corresponds to having absorbed 100 parts by mass of water as the cellulose fiber swelling agent with respect to 100 parts by mass of the pulp sheet (in terms of absolute dry mass). To this pulp sheet, 90 parts by mass of a polypropylene resin (BC05B, manufactured by Nippon Polypro), 5 parts by mass of a maleic anhydride-modified polypropylene resin (Yumex 1010, manufactured by San Nopco) as a fluidity improver, and titanium dioxide (Typaque A-220, 6 parts by mass of Ishihara Sangyo), 1 part by mass of calcium hydroxide (reagent grade 1, Wako Pure Chemical Industries) as a pH adjuster, and 0.5 parts by mass of a surfactant (Evan 450, manufactured by Daiichi Kogyo Seiyaku) Was mixed to 170 ° C. with a high-speed stirring mixer. Thereafter, 0.5 parts by mass of SBH powder (Morton International) as a bleaching agent was added and mixed uniformly. Then, this mixture was non-screw type granulator with a diameter of 3 mm, a length of 5 mm, a water content of 0.5% by mass, A cylindrical pellet having an apparent specific gravity of 0.53 was obtained. Next, the cylindrical pellet was supplied to a twin-screw extruder having the same degassing step as in Example 1, and a pellet made of a paper-containing thermoplastic resin composition was obtained from kneading pelletization. The results are shown in Table 1.

(Examples 8 to 12)
In Example 6, the SBH powder was mixed at the addition rate shown in Table 2. Subsequently, it pelletized with the non-screw type granulator, and the pellet which consists of a final paper compounding thermoplastic resin composition was obtained. 50 g of pellets made of this paper-blended thermoplastic resin composition and 30 ml of distilled water were placed in a polyethylene bag, and air was discharged as much as possible and kept at 35 ° C. for 2 days. Thereafter, the degree of coloration of the water layer was evaluated visually. Further, the absorbance of the filtered aqueous layer at a wavelength of 400 nm was measured using a spectrophotometer. The results are shown in Table 2.

(Comparative Example 1)
68 parts by mass of polypropylene resin (BC05B, manufactured by Nippon Polypro Co., Ltd.) and maleic anhydride-modified as a fluidity improver for 100 parts by mass of the pulverized material passing through the 1 mm square hole screen of the pre-dried milk carton trimming waste of Example 1 3 parts by mass of a polypropylene resin (Yumex 1010 manufactured by San Nopco) and 1 part by mass of zinc stearate as a surfactant were blended to obtain a mixture for kneading. No cellulose fiber swelling agent is added to the kneading mixture. The kneading mixture was heated to 180 ° C. with a high-speed stirring mixer. Next, after cooling, an amorphous intermediate kneaded product having an apparent specific gravity of 0.3 was obtained. After that, the amorphous intermediate kneaded product is unstable in the supply to the twin screw extruder, the load fluctuation of the extruder motor power is large, the resin temperature is 190 ° C, heat is generated, and the white smoke and the pellets adhere to each other at the exit of the extruder. Vigorously observed. The results are shown in Table 1.

(Comparative Example 2)
In Example 4, pellets made of a paper-containing thermoplastic resin composition were obtained in the same manner as in Example 4 except that the cellulose fiber swelling agent, the surfactant, and the bleaching agent were not used. The load fluctuation of the twin-screw extruder motor power was large, the resin temperature generated 185 ° C., and white smoke and pellets adhered to the exit of the extruder were observed. The results are shown in Table 1.

(Comparative Example 3)
In Example 6, pellets made of a paper-containing thermoplastic resin composition were obtained in the same manner as in Example 6 except that SBH and cellulose fiber swelling agent were not added. The results are shown in Tables 1 and 2.

  Examples 1 to 7 were uniform with no rounding and agglomeration of cellulose fibers and could withstand practical use, and were colorless or almost colorless from the water elution test and withstand practical use. On the other hand, Comparative Examples 1 and 2 to which no cellulose fiber swelling agent was added were inferior in cellulose dispersibility and yellowing resistance. Comparative Example 3 was inferior in yellowing resistance based on the water elution test because SBH was not added as compared with Example 6.

Referring to Examples 8 to 12 and Comparative Example 3, yellowing resistance was developed even in Example 8 in which SBH was slightly added, and the effect increased as the amount added increased. The SBH addition rate (mass%) was further improved when it was 0.10 or more.

Claims (13)

  Cellulose fiber swelling agent is absorbed into 2 to 30 parts by mass of 100 parts by mass of the cylindrical pellets in cylindrical pellets formed by pulverized plastic film laminated paper with a non-screw type granulator. Paper pellets. In a method for producing a paper-containing thermoplastic resin composition containing pulp or crushed waste paper and a thermoplastic resin, and compounded by kneading,
A method for producing a paper-containing thermoplastic resin composition comprising a step of heat-kneading a mixture or composition containing the pulp or the crushed waste paper and the thermoplastic resin in the presence of a cellulose fiber swelling agent. The paper pellet according to claim 1, a mixture containing pulp or crushed waste paper and a thermoplastic resin, a composition containing pulp or crushed waste paper and a thermoplastic resin, or the mixture or the composition is melted with a high-speed mixer. Kneading in which 2 to 300 parts by mass of cellulose fiber swelling agent and 10 to 200 parts by mass of thermoplastic resin are added to 100 parts by mass of any one of the cylindrical pellets molded by a non-screw type granulator or a mixture thereof. Adjusting the mixture for use;
And a step of heat-kneading the kneading mixture in the presence of the cellulose fiber swelling agent. A method for producing a paper-containing thermoplastic resin composition, comprising: A step of adjusting a kneading mixture in which at least 10 to 200 parts by mass of a thermoplastic resin are added to 100 parts by mass of the paper pellets according to claim 1;
And a step of heating and kneading the kneading mixture in the presence of a cellulose fiber swelling agent absorbed in the paper pellets, and a method for producing a paper-containing thermoplastic resin composition. A mixture containing pulp or crushed waste paper and thermoplastic resin, a composition containing pulp or crushed waste paper and thermoplastic resin, or a resin melt of the mixture or the composition with a high-speed mixer and molding with a non-screw type granulator A step of adjusting a kneading mixture in which at least 2 to 300 parts by mass of a cellulose fiber swelling agent is added to 100 parts by mass of any one of the cylindrical pellets or a mixture thereof;
And a step of heat-kneading the kneading mixture in the presence of the cellulose fiber swelling agent. A method for producing a paper-containing thermoplastic resin composition, comprising: In the heating and kneading step,
6. The method for producing a paper-containing thermoplastic resin composition according to claim 2, 3, 4 or 5, wherein the paper pellets or the columnar pellets or both of them are unraveled. In the heating and kneading step,
The method for producing a paper-containing thermoplastic resin composition according to claim 2, 3, 4, 5, or 6, characterized in that defibration of paper contained in the kneading mixture is advanced. In the heating and kneading step,
The method for producing a paper-containing thermoplastic resin composition according to claim 7, wherein the fibrillated cellulose fibers are rounded.   The pulp or the crushed waste paper is finely pulverized paper, defibrated paper, coarsely pulverized paper having a diameter of 0.5 mm to 3 mm, coarsely pulverized plastic film having a diameter of 0.5 mm to 3 mm A laminated paper, a wet pulp having a moisture content of 40 to 65% by mass, a pulp sheet for papermaking having a moisture content of 5 to 50% by mass, or a mixture thereof. Or the manufacturing method of the paper mixing thermoplastic resin composition of 8.   The said cellulose fiber swelling agent is water, The manufacturing method of the paper mixing thermoplastic resin composition of Claim 2, 3, 4, 5, 6, 7, 8, or 9 characterized by the above-mentioned.   A surfactant and / or a bleaching agent is added in the step of adjusting the kneading mixture or the heating and kneading step. Or the manufacturing method of the paper mixing thermoplastic resin composition of 10.   The paper-containing thermoplastic resin composition obtained through the heat-kneading step and a bleaching agent are further included, wherein the step further comprises the step of bringing the paper-containing thermoplastic resin composition into contact with a bleaching agent. A method for producing a paper-containing thermoplastic resin composition according to 10 or 11. The method for producing a paper-containing thermoplastic resin composition according to claim 11 or 12, wherein the bleaching agent is a borohydride compound.