JP2008075014A - Paper-containing resin composition and molded product thereof, and method for producing them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper-containing resin composition aimed at resource utilization through reusing the whole of hard-to-recycle laminated paper, that is, through homogeneously mixing and dispersing ground paper with undispersed paper eliminated by improving the kneadability between a resin material and esterified ground paper of rough particle size without making ground paper particle size small to effect improving the fluidity of the final composition. <P>SOLUTION: The paper-containing resin composition comprises a pulverized sheet of the paper esterified by a polybasic acid anhydride, a polypropylene resin, a polyethylene resin and an alkaline earth metal compound, wherein the ground paper and the polypropylene resin are the main components. This resin composition is 2.0-25.0 g/10 min in melt mass flow rate(MFR)(test temperature is 190°C, test load is 10 kg) specified in ASTM-D1238-04c. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a paper-containing resin composition obtained by pulverizing laminated paper that is difficult to regenerate, such as printing cutting waste from a liquid container or a collected liquid container, and mixing it with a resin raw material. More specifically, by improving the kneadability between the coarsely pulverized pulverized product and the resin raw material, the undispersed laminate paper is eliminated and uniformly mixed and dispersed. As a result, the fluidity of the paper-containing resin composition is improved. The present invention relates to a paper-containing polyolefin resin composition capable of increasing the content of laminated paper by improving.

  Conventionally, a method of reusing waste laminated paper has been performed. Several methods have been proposed for dry reuse of plastic film laminated paper. The dry recycling methods are roughly divided into proposals for pulverization (pulverizer and pulverized particle size), kneading with thermoplastic resin (mixing chemical and resin blending ratio), and granulation. The purpose of this is to improve the moldability by increasing the mixing and dispersion. It is known that the fluidity of the mixed composition of resin and pulverized paper decreases as the pulverized particle size of the paper becomes coarse and the ratio of the pulverized paper increases.

  As for the pulverization method for improving the kneadability with resin, for example, plastic film laminated paper has a median value in the range of 0.05 mm to 0.3 mm in the particle size of the shredded product, and the fiber of the paper is defibrated. A method of cutting the material so as not to cause the shredded product (see, for example, Patent Document 1), a method of roughly pulverizing into a flake shape having a particle size of about 3 mm, and then impact-pulverizing (for example, see Patent Document 2) ), A method of improving the dispersibility of paper and resin by finely pulverizing the particle size of the pulverized product to 5 mm or less, preferably 1 mm or less on one side and defibrating the fibers into a cotton-like shape (for example, patents) Reference 3), and a method of using finely pulverized 100-mesh pass after pulverizing polypropylene laminated waste paper to 3 mm square (for example, see Patent Document 4).

  On the other hand, with regard to kneading chemicals, a shredded composite paper having a polyethylene resin layer or a polypropylene resin layer on both sides or one side is used for a paper-resin mixing using a shredded polyethylene resin or polypropylene resin with a small specific gravity difference. A method of preventing uneven dispersion (see, for example, Patent Document 5), and reusing unnecessary plastic-laminated paper and resin-coated paper by defining the pellet resin melt flow rate (MFR) to 5-50. There is a method (for example, refer to Patent Document 6).

  For esterification with polybasic acid anhydrides, there is a method for producing polyolefin resin composites containing polyolefin, wood-based materials such as wood flour and wood pulp, polybasic acid anhydrides and organic peroxides, and heating. It is said that molding processability and mechanical strength are increased by kneading (see, for example, Patent Document 7). In addition, with respect to resin compositions containing wood flour, in particular, a method for preventing corrosion of molds such as injection molding by adding magnesium oxide as a neutralizing agent for organic acids generated by thermal decomposition of wood flour during heating and pressing. (For example, refer to Patent Document 8).

JP 2001-310326 A JP 2003-96206 A JP 2003-335951 A JP-A-11-293124 Japanese Patent Laid-Open No. 10-138241 Japanese Patent Laid-Open No. 10-29222 Japanese Patent No. 36551117 JP-A 63-139946

  In the method of reusing recycled waste paper by wet method, it is necessary to separate the paper and film, the yield of separated and recovered fibers is low, and further processing such as incineration and landfilling of the separated laminated film However, a method for efficiently reusing the entire laminated waste paper has not been put into practical use. Furthermore, a method for reusing recycled laminated paper as it is without separation has not been put to practical use.

  Each of the methods disclosed in Patent Documents 1, 2, or 3 enhances the mixing and dispersion of fibers in the resin by reducing the pulverized particle size of the paper or by defining the shape of the pulverized product. is there. However, the finer the particle size, there is a disadvantage that the polyethylene having a relatively low melting point contained in the plastic film laminated paper melts due to heat generated during crushing, and the crushing efficiency is remarkably reduced, such as clogging of the screen. Even in the method shown in Patent Document 4, when the laminated paper is pulverized, the smaller the pulverized particle size, the more easily clogging of the screen or the flat net due to heat melting of the laminated resin occurs. Problems such as contact between the fixed blade and the rotary blade due to temperature rise occur.

  When the plastic film laminated paper is a laminated paper mainly composed of softwood bleached chemical pulp, the strength of the paper is high, but the basis weight is high, both sides of the paper are covered with a resin layer such as thick polyethylene, and the rigidity is also high, It is difficult to pulverize. The reason why fine pulverization is difficult is the same as in Patent Documents 1, 2, 3 or 4, and a resin such as polyethylene having a relatively low melting point melts due to heat generated during pulverization, thereby causing clogging of the screen. , Remarkably reducing the pulverization efficiency. Therefore, establishment of a technique for improving the kneading dispersibility of the pulverized laminate paper having a coarse particle size and the resin and utilizing a resin composition having a high paper blending ratio for injection molding is a problem.

  The first object of the present invention is a hard-to-regenerate laminate that contains a large amount of printing wastes from liquid containers and / or long-fiber softwood bleached chemical pulp collected from liquid containers, which has conventionally been used only for incineration or fiber content. An object of the present invention is to provide a paper-containing resin composition aiming at effective utilization of resources by reusing paper as it is as a whole without separating paper and film. That is, without reducing the pulverized particle size of the laminated paper, by improving the kneadability between the coarsely pulverized pulverized product and the resin raw material, the laminated paper is uniformly mixed and dispersed without any undispersed material. An object of the present invention is to provide a paper-containing resin composition having good moldability such as injection molding even when the content of laminated paper is increased by improving the fluidity of the paper-containing resin composition.

  A second object of the present invention is to use a paper-containing resin composition according to the present invention, a high content of laminated paper, no discoloration and odor, low water absorption, and excellent impact strength. Is to provide goods.

  The third object of the present invention is to provide a production method for obtaining a paper-containing resin composition in which laminated paper is not dispersed and is uniformly mixed and dispersed by kneading using a twin-screw extruder. There is.

  The fourth object of the present invention is to provide a production method for obtaining a well-formed paper-containing resin molded article using the paper-containing resin composition of the present invention.

  The present inventors diligently investigated the relationship between the composition of the paper used for the pulverized paper and the pulverized product, and the relationship between the workability when the resin was mixed and the quality of the paper-containing resin composition. As a result, the inventors have found that the above objects can be achieved at the same time, and have reached the present invention.

  The paper-containing resin composition according to the present invention contains at least a pulverized paper esterified with a polybasic acid anhydride, a polypropylene resin, a polyethylene resin, and an alkaline earth metal compound. It is a main component and is characterized in that the melt mass flow rate (MFR) (test temperature = 190 ° C., test load = 10 kg) defined by ASTM-D1238-04c is 2.0 to 25.0 g / 10 min.

  In the paper-containing resin composition according to the present invention, the polybasic acid anhydride is maleic anhydride, and the proportion of maleic anhydride introduced by esterification is 0.1 to 5% by mass with respect to the pulp component. It is preferable that The fluidity of the paper-containing resin composition is improved and the water absorption rate is reduced. There is no undispersed laminate paper and it is easy to mix and disperse uniformly.

  In the paper-containing resin composition according to the present invention, it is preferable that the alkaline earth metal compound is a magnesium compound and is contained in an amount of 0.1 to 5% by mass with respect to the total mass in terms of magnesium oxide. By neutralizing the organic acid, it is possible to suppress discoloration and odor generation.

  In the paper-containing resin composition according to the present invention, the paper is a polyethylene film laminated paper based on a base paper containing 50% by mass or more of softwood bleached chemical pulp, and the polyethylene resin is derived from the polyethylene film laminated paper. It is preferable that Milk cartons and their cut waste are reused, and the strength of the paper-containing resin composition is increased by containing a large amount of softwood bleached chemical pulp.

  In the paper-containing resin composition according to the present invention, the total amount of the paper material including the pulverized material and the filler is preferably 51% by mass or more. That is, it can be set as an environment-friendly paper-containing resin composition.

  The paper-containing resin molded product according to the present invention contains at least a pulverized paper esterified with a polybasic acid anhydride, a polypropylene resin, a polyethylene resin, and an alkaline earth metal compound, and the pulverized product and the polypropylene resin are It is a main component and is characterized in that the melt mass flow rate (MFR) (test temperature = 190 ° C., test load = 10 kg) defined by ASTM-D1238-04c is 2.0 to 25.0 g / 10 min.

  In the paper-containing resin molded product according to the present invention, the paper is a polyethylene film laminated paper based on a base paper containing 50% by mass or more of softwood bleached chemical pulp, and the polyethylene resin is derived from the polyethylene film laminated paper. It is preferable that Milk cartons and their cut waste are reused, and the strength of the paper-containing resin composition is increased by containing a large amount of softwood bleached chemical pulp.

  The method for producing a paper-containing resin composition according to the present invention includes a step of pulverizing a polyethylene film laminated paper based on a base paper containing 50% by mass or more of softwood bleached chemical pulp to obtain a pulverized paper, and a polybasic acid A step of esterifying the pulverized product with an anhydride, a step of neutralizing an organic acid with an alkaline earth metal compound, and at least the pulverized product and a polypropylene resin are kneaded with a twin screw extruder, and ASTM-D1238- And a step of obtaining a paper-containing resin composition having a melt mass flow rate (MFR) specified in 04c (test temperature = 190 ° C., test load = 10 kg) of 2.0 to 25.0 g / 10 min. To do.

  In the method for producing a paper-containing resin composition according to the present invention, the pulverized product preferably has a pulverized particle size of 0.5 to 2.5 mm. Good kneadability can be obtained, pulverization is easy, and long run operation is possible.

  In the method for producing a paper-containing resin composition according to the present invention, the polyethylene film laminated paper is a polyethylene film laminated paper for a liquid container, cutting waste of the polyethylene film laminated paper, and / or recovered waste paper of the polyethylene film laminated paper. Preferably there is. That is, the efficiency of effective use of resources increases.

  The method for producing a paper-containing resin molded product according to the present invention includes a step of pulverizing a polyethylene film laminated paper based on a base paper containing 50% by mass or more of softwood bleached chemical pulp to obtain a pulverized paper product, and a polybasic acid A step of esterifying the pulverized product with an anhydride, a step of neutralizing an organic acid with an alkaline earth metal compound, and at least the pulverized product and a polypropylene resin are kneaded with a twin screw extruder, and a paper-containing resin composition And a melt mass flow rate (MFR) defined by ASTM-D1238-04c (test temperature = 190 ° C., test load = 10 kg) is obtained by molding the paper-containing resin composition with an injection molding machine. And a step of obtaining a paper-containing resin molded product of 0 to 25.0 g / 10 min.

  In the method for producing a paper-containing resin molded product according to the present invention, the pulverized product preferably has a pulverized particle size of 0.5 to 2.5 mm. Good kneadability can be obtained, pulverization is easy, and long run operation is possible.

  In the method for producing a paper-containing resin molded product according to the present invention, the polyethylene film laminated paper is a polyethylene film laminated paper for a liquid container, cutting waste of the polyethylene film laminated paper, and / or recovered waste paper of the polyethylene film laminated paper. Preferably there is. That is, the efficiency of effective use of resources increases.

  In the method for producing a paper-containing resin molded product according to the present invention, it is preferable to add a fluidity improver in the step of obtaining the paper-containing resin composition and / or the step of obtaining the paper-containing resin molded product. Heat generation during kneading and / or heat generation during molding is suppressed, and moldability is improved.

  With the paper-containing resin composition of the present invention, the entire printing waste and / or the recovered liquid container of the liquid container, which has conventionally been used only for incineration or fiber, can be reused. In particular, the liquid container is made of hard-to-recycle laminated paper containing a lot of long-fiber softwood bleached chemical pulp, and the whole can be reused. That is, the paper-containing resin composition of the present invention improves the kneadability between the coarsely pulverized product and the resin raw material without reducing the pulverized particle size of the laminated paper, thereby reducing the undispersed material of the laminated paper. Without being mixed and dispersed uniformly, as a result, by improving the fluidity of the paper-containing resin composition, the moldability such as injection molding is good even when the content of the laminated paper is increased.

  By using the paper-containing resin composition according to the present invention, the paper-containing resin molded product of the present invention can increase the content of the laminated paper, and is excellent in impact strength without discoloration and odor.

  In the method for producing the paper-containing resin composition of the present invention, the reaction with the polybasic acid anhydride and the alkaline earth metal compound is caused, and kneading using a twin-screw extruder is performed so that the undispersed laminate paper is removed. A paper-containing resin composition having good fluidity that is uniformly mixed and dispersed can be obtained.

  In the method for producing a paper-containing resin molded article of the present invention, a paper-containing resin molded article that has been well molded can be obtained using the paper-containing resin composition of the present invention.

  The details of the present invention will be described, but the present invention is not construed as being limited to the following embodiments.

  The paper-containing resin composition according to this embodiment contains at least a pulverized paper esterified with a polybasic acid anhydride, a polypropylene resin, a polyethylene resin, and an alkaline earth metal compound, and the pulverized material and the polypropylene resin. Is the main component, and the melt mass flow rate (MFR) (test temperature = 190 ° C., test load = 10 kg) specified by ASTM-D1238-04c is 2.0 to 25.0 g / 10 min. The paper is a laminated paper based on a base paper containing 50% by mass or more of softwood bleached chemical pulp, or a combination of the laminated paper and the base paper before lamination.

The laminated paper has a polyethylene resin having a film thickness of 20 to 50 μm laminated on one or both sides of the base paper. Here, the laminated paper is a single use of a laminated paper for a liquid container, a laminated paper cutting waste or a recycled waste paper of a laminated paper, or a combination of laminated paper and laminated paper cutting waste, a laminated paper and a laminated paper. Use of a combination of recovered recovered paper, use of a combination of cut waste of laminated paper and recovered recovered paper of laminated paper, or use of a combination of recovered waste paper of laminated paper and laminated paper and recovered recovered paper of laminated paper Is preferred. Increases the efficiency of effective use of resources. A typical example thereof is a laminated paper for a liquid container called a so-called milk carton, or printing cut waste (hereinafter referred to as “print trimming waste”), or recovered paper such as a milk pack (hereinafter referred to as “milk trimming waste”). These are collectively called “laminated waste paper”.) The base paper preferably has a basis weight of 300 to 500 g / m ² , a paper thickness of 0.4 to 0.6 mm, and a density of 0.7 to 0.6 g / cm ³ . The pulp constituting the base paper of the laminate paper is mainly softwood bleached chemical pulp (NBKP), and the blending ratio of NBKP in the base paper is at least 50% by mass or more. More preferably, it is 80 mass% or more. If the NBKP content is less than 50% by mass, the strength suitability of the paper-containing resin composition of the present embodiment tends to be insufficient. As a material of the laminated film, for example, a low density polyethylene resin or a high density polyethylene resin is used.

  A pulverized product is obtained by pulverizing the laminated paper. In addition, you may obtain a pulverized material by grind | pulverizing what mixed the base paper with the laminate paper. Thus, the pulverized product always contains polyethylene derived from the polyethylene film of the laminated paper. The content of polyethylene contained in the paper-containing resin composition according to this embodiment is, for example, 2 to 10% by mass, and preferably 4 to 8% by mass. This content can be appropriately adjusted depending on the blended amount of the pulverized paper and the amount of base paper added before lamination. The pulverized particle size of the pulverized product is preferably 0.5 to 2.5 mm, although it is affected by the subsequent kneading conditions. More preferably, it is 1.0-2.0 mm. The particle diameter of the pulverized paper is defined by the diameter of the screen obtained by passing through a predetermined screen (hereinafter simply referred to as “particle diameter”). In order to improve the kneadability with the resin, the finer the particle size of the paper, the better. By setting the pulverized particle size to 2.5 mm or less, good kneadability is easily obtained. When crushing laminated paper that is laminated with heat-meltable resin such as polyethylene, the crushing of the screen or flat screen due to heat melting of the resin is more likely to occur as the pulverized particle size becomes smaller, and the temperature inside the crusher rises. Problems such as contact between the fixed blade and the rotary blade due to the above are likely to occur. According to the experiments by the present inventors, particularly when pulverizing to a particle size of less than 0.5 mm, the operation of the pulverizer becomes extremely difficult. However, when the particle size is 0.5 mm or more, this type of trouble hardly occurs and a long run operation is possible, and the grinding efficiency is improved.

  In this embodiment, the resin added together with the pulverized paper is a polypropylene resin (PP resin) or a modified resin thereof. In the present embodiment, the following resin may be added together with the polypropylene resin or the modified resin thereof. Examples thereof include general-purpose resins such as polyethylene resins, polystyrene resins, acrylonitrile / butadiene / styrene resins, acrylonitrile / styrene resins, urethane resins, polyester resins, polycarbonate resins, and modified resins thereof. These resins may be newly synthesized products, pulverized products or recycled products of used molded products, and may be used alone or as a mixture.

  In the paper-containing resin composition according to this embodiment, a pulverized product and a polypropylene resin are main components, and the total content thereof is preferably 85 to 98% by mass, more preferably 90 to 95% by mass. is there. If it is less than 85% by mass, the fluidity and dispersibility may be inferior, and if it exceeds 98% by mass, the color change may be noticeable. Here, the content of the pulverized product is preferably 50 to 70% by mass, and more preferably 55 to 60% by mass. When the amount is less than 50% by mass, the amount of pulverized material mixed is reduced, resulting in poor recycling efficiency. When the amount exceeds 70% by mass, fluidity and dispersibility may be inferior. Moreover, it is preferable that content of a polypropylene resin shall be 15-48 mass%, More preferably, it is 25-43 mass%. If the amount is less than 15% by mass, the strength may decrease. If the amount exceeds 48% by mass, the amount of pulverized material mixed in decreases, resulting in poor recycling efficiency.

  The polybasic acid anhydride used in the present embodiment is, for example, maleic anhydride, phthalic anhydride or succinic anhydride, and is selectively added to the pulverized laminate paper before kneading with the resin. By esterifying cellulose and hemicellulose in the fiber, it is effective in improving the fluidity of the pulverized product having a coarse particle size without reducing the pulverized particle size of the paper. Among these, maleic anhydride is more preferable, and the addition amount is selected in the range of 0.1 to 5% by mass. More preferably, it is 0.5-3 mass%. If this amount is less than 0.1% by mass, the effect of improving the fluidity may be insufficient, and if it exceeds 5% by mass, the physical properties of the paper-containing resin composition and the paper-containing resin molded product may be deteriorated.

  The alkaline earth metal compound used in the present embodiment includes, for example, magnesium oxide, calcium oxide, zinc oxide and the like, added when kneading with a resin, and after reacting with moisture in the pulp and changing to a hydroxide, By neutralizing the polybasic acid remaining after esterification and / or the organic acid generated by thermal decomposition of the pulp, it is effective to prevent the generation of odor and gas. Among these, magnesium oxide is more preferable, and the addition amount is selected in the range of 0.1 to 5% by mass with respect to the total mass of the paper-containing resin composition according to the present embodiment. More preferably, it is 0.5-3 mass%. If this amount is less than 0.1% by mass, the neutralization effect may be insufficient. If it exceeds 5% by mass, the physical properties of the paper-containing resin composition and the paper-containing resin molded product may be reduced, and the economy may be reduced. Is not preferable. When a paper-containing resin composition is formed, for example, when magnesium oxide is added, magnesium oxide is converted to a magnesium compound by the neutralization reaction, but the content of magnesium oxide is measured from the state of the paper-containing resin composition. If so, obtain it in terms of magnesium oxide.

  In the paper-containing resin composition of the present embodiment, components other than the pulverized paper and resin may be included as necessary. For example, a fluidity improver may be added.

  The addition of the fluidity improver used in the present embodiment is either when blended when kneaded the pulverized paper pulverized product and the resin, or when blended when molding the paper-containing resin composition But you can. By containing a fluidity improver, heat generation during molding is prevented, and moldability during molding is improved. In addition, when mix | blending a fluidity improver at the time of kneading | mixing, not only the effect at the time of shaping | molding but the effect which prevents the heat_generation | fever by friction at the time of kneading | mixing is also acquired. The fluidity improver is not particularly limited as long as it prevents heat generation due to friction during molding and improves the fluidity of the paper-containing resin composition. For example, polyethylene wax, low density polyethylene, stearic acid, stearic acid Examples include higher fatty acids such as zinc and calcium stearate or salts thereof, and various higher fatty acid esters. The melting point of the fluidity improver is preferably 100 ° C. or lower, and examples thereof include fatty acid amides such as erucic acid amide, oleic acid amide, and stearic acid amide. One kind of these may be used, or two or more kinds may be used in combination.

  Moreover, you may add auxiliary agents, such as a compatibilizing agent, resin antioxidant, and an antistatic agent, as needed, in the range which does not affect the effect of this invention. In order to increase the whiteness, a small amount of filler such as titanium oxide, talc, calcium carbonate may be added.

  In the paper-containing resin composition according to the present embodiment, the total amount of paper materials including the pulverized paper material and the filler is preferably 51% by mass or more. It can be set as an environment-friendly paper-containing resin composition. More preferably, it is 51-70 mass%. Components other than the paper material in the paper-containing resin composition are mainly composed of a resin. In the case of a laminated paper, the pulverized paper includes all the constituents. For example, NBKP, pulp other than NBKP, resin content in base paper, filler in base paper, and laminate film are included. The filler is added as necessary when the pulverized paper and the resin are kneaded.

  The paper-containing resin composition of the present embodiment is preferably kneaded with a twin-screw extruder, and at this time, the amount of undispersed material is reduced and is easily homogenized. The treatment with a twin screw extruder is preferable because it can be more homogeneous twice or more than once. At this time, it is more preferable to knead | mix at the temperature of 100-200 degreeC. Before kneading with a twin screw extruder, paper pulverized material and resin weighed to a predetermined ratio, and auxiliary agents such as a fluidity improver to be added as necessary are uniformly mixed in a mixer such as a Henschel mixer. It is preferable to mix them. The fibers are defibrated and cut by the flow and kneading action of the screw of the twin screw extruder, and the dispersibility and fluidity of the paper-containing resin composition are improved.

  In the paper-containing resin composition according to this embodiment, the MFR (test temperature = 190 ° C., test load = 10 kg) defined by ASTM-D1238-04c is 2.0 to 25.0 g / 10 min. Preferably, it is 5.0-22.0 g / 10min. The paper-containing resin composition whose MFR falls within this range is sufficiently uniform between the pulverized paper and the resin even though it contains a pulverized paper based on a base paper containing NBKP of 50% by mass or more. Is distributed. When the MFR is less than 2.0 g / 10 min, dispersion of the pulverized paper and the resin is insufficient. Further, in the present embodiment containing a large amount of NBKP, when the pulverized paper and the resin are sufficiently dispersed, the MFR approaches 25.0 g / 10 min. The value of this MFR is not greatly affected by the presence or absence of the addition of a fluidity improver when kneading with a twin screw extruder. Moreover, it is preferable that the water absorptivity measured according to JIS K 7209: 2000 "Plastics-Determination of water absorptivity" D method is less than 0.10. The tensile strength measured according to JIS K 7113: 1995 “Plastic Tensile Test Method” is preferably 33 MPa or more. Furthermore, it is preferable that the bending strength measured according to JIS K 7203: 1995 “Bending test method of hard plastic” is 63 MPa or more.

  Thus, the paper-containing resin composition according to this embodiment includes a step of pulverizing a polyethylene film laminated paper based on a base paper containing 50% by mass or more of softwood bleached chemical pulp to obtain a pulverized paper, and a polybasic A step of esterifying the pulverized product with an acid anhydride, a step of neutralizing an organic acid with an alkaline earth metal compound, and at least the pulverized product and a polypropylene resin are kneaded with a twin screw extruder, and ASTM-D1238. And a step of obtaining a paper-containing resin composition having a melt mass flow rate (MFR) (test temperature = 190 ° C., test load = 10 kg) of 2.0 to 25.0 g / 10 min as defined in -04c. Obtainable. The base paper before lamination may be added to the laminated paper.

  Next, the paper-containing resin molded product according to this embodiment includes a step of pulverizing a polyethylene film laminated paper based on a base paper containing 50% by mass or more of softwood bleached chemical pulp to obtain a pulverized paper product, and a polybasic acid A step of esterifying the pulverized product with an anhydride, a step of neutralizing an organic acid with an alkaline earth metal compound, and at least the pulverized product and a polypropylene resin are kneaded with a twin screw extruder, and a paper-containing resin composition And a melt mass flow rate (MFR) defined by ASTM-D1238-04c (test temperature = 190 ° C., test load = 10 kg) is obtained by molding the paper-containing resin composition with an injection molding machine. And a step of obtaining a paper-containing resin molded product having a size of 0 to 25.0 g / 10 min. Here, it is preferable to add a fluidity improver in the step of obtaining the paper-containing resin composition and / or the step of obtaining the paper-containing resin molded product.

  The paper-containing resin molded article according to this embodiment thus obtained contains at least a pulverized paper esterified with a polybasic acid anhydride, a polypropylene resin, a polyethylene resin, and an alkaline earth metal compound, The pulverized product and the polypropylene resin are main components, and the melt mass flow rate (MFR) (test temperature = 190 ° C., test load = 10 kg) defined by ASTM-D1238-04c is 2.0 to 25.0 g / 10 min. The paper preferably contains 50% by mass or more of NBKP. Further, the MFR is more preferably 5.0 to 22.0 g / 10 min. The MFR value of the paper-containing resin composition and the MFR value after making the paper-containing resin molded product are substantially the same. This paper-containing resin molded product is free from discoloration and odor and has excellent impact strength.

  In the paper-containing resin molded product of the present embodiment, the laminated paper contained is a polyethylene film laminated paper for liquid containers, cutting scraps of the polyethylene film laminated paper, and / or recovered waste paper of the polyethylene film laminated paper. And effective use of resources. Moreover, it is preferable that the total amount of the paper material including the pulverized paper and the filler in the paper-containing resin molded product is 51% by mass or more, which is an environment-friendly type. Examples of the paper-containing resin molded product include a dish, a cup, a bowl, a spoon, and a comb.

  Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. Further, “%” in the examples represents “% by mass” unless otherwise specified.

(Example 1)
[Manufacture of crushed paper]
The base paper of the polyethylene film laminated paper contains 90% by mass of NBKP, grinds the milk carton printing trimming waste having a basis weight of 393 g / m ² , a thickness of 0.48 mm, and a density of 0.82 g / cm ³ (model BO-2575). And HaA-2542: manufactured by Horai Co., Ltd.) and passed through a 0.5 mmφ screen to obtain a pulverized polyethylene film laminated paper.
[Production of paper-containing resin composition]
Subsequently, maleic anhydride (trade name: maleic anhydride: manufactured by Nippon Oil & Fats Co., Ltd.) was added in an amount of 0.5% by mass with respect to the pulp component, and titanium oxide (trade name: Typaque A-220: Ishihara Sangyo Co., Ltd.) was added to the pulverized product. Manufactured), modified PP resin (trade name: Umex 1010: manufactured by San Nopco) and PP resin (trade name: J-5051HP: manufactured by Idemitsu Petrochemical Co., Ltd.), and magnesium oxide (trade name: magnesium oxide: Tomita Pharmaceutical) Add 0.5% by mass to the total mass, mix uniformly with a Henschel mixer, and then put into a desk pelleter (model F-60: manufactured by Fuji Powder Co., Ltd.) and a twin screw extruder. And pelletized to obtain a paper-containing resin composition. The paper ratio in this paper-containing resin composition was 55% by mass.
[Manufacture of injection molded products for evaluation]
From the paper-containing resin composition, an injection molded product for evaluation was produced using an injection molding machine (model J35ELII: manufactured by Nippon Steel Works) with a cylinder set temperature of 180 ° C.

(Example 2)
In the production of the pulverized paper of Example 1, the screen was changed from a 0.5 mmφ screen to a 1.0 mmφ screen, and maleic anhydride (trade name: maleic anhydride: manufactured by NOF Corporation) was adjusted to 0.000 with respect to the pulp components. The amount is changed from 5% by mass to 1.5% by mass, and magnesium oxide (trade name: Magnesium oxide: manufactured by Tomita Pharmaceutical Co., Ltd.) as a neutralizing agent is 0.5% by mass to 1.5% by mass with respect to the total mass. A paper-containing resin composition and an evaluation injection-molded product were obtained in the same manner except that the amount was changed. The paper ratio in this paper-containing resin composition was 55% by mass.

(Example 3)
In the production of the paper pulverized product of Example 2, the raw material of the pulverized product was made from milk carton printing trimming waste, the base paper of the polyethylene film laminated paper contained 80% by mass of NBKP, the basis weight was 362 g / m ² , and the thickness was 0.00. A paper-containing resin composition and an evaluation injection-molded product were obtained in the same manner except that the recovered milk pack was changed to 47 mm and density 0.78 g / cm ³ . The paper ratio in this paper-containing resin composition was 55% by mass.

Example 4
In the production of the paper-containing resin composition of Example 3, the blended amount of the paper pulverized product was changed from the amount that the paper ratio in the paper-containing resin composition was 55% by mass to the paper ratio in the paper-containing resin composition. In the production of the pulverized paper of Example 3, the screen was changed from a 1.0 mmφ screen to a 2.0 mmφ screen in the production of the crushed paper of Example 3, and maleic anhydride (trade name: maleic anhydride: Nippon Oil & Fats) The product was changed from 1.5% by mass to 2.0% by mass with respect to the pulp component, and magnesium oxide (trade name: Magnesium oxide: manufactured by Tomita Pharmaceutical Co., Ltd.) as a neutralizing agent was 1. A paper-containing resin composition and an evaluation injection molded product were obtained in the same manner except that the amount was changed from 5% by mass to 2.0% by mass.

(Comparative Example 1)
In the production of the pulverized paper of Example 1, the screen was changed from a 0.5 mmφ screen to a 3.0 mmφ screen, and magnesium oxide (trade name magnesium oxide: manufactured by Tomita Pharmaceutical Co., Ltd.) was not added as a neutralizing agent. Except for the above, a paper-containing resin composition and an evaluation injection-molded product were obtained in the same manner. The paper ratio in this paper-containing resin composition was 55% by mass.

(Comparative Example 2)
In the production of the paper-containing resin composition of Example 1, maleic anhydride (trade name: maleic anhydride: manufactured by Nippon Oil & Fats Co., Ltd.) was changed from 0.5% by mass to no addition to the pulp component, and oxidized as a neutralizing agent. A paper-containing resin composition and an injection-molded product for evaluation were obtained in the same manner except that magnesium (trade name: magnesium oxide: manufactured by Tomita Pharmaceutical Co., Ltd.) was changed from 0.5% by mass to no additive with respect to the total mass. .

(Comparative Example 3)
In the production of the paper-containing resin composition of Example 3, maleic anhydride (trade name: maleic anhydride: manufactured by Nippon Oil & Fats Co., Ltd.) was changed from 1.5% by mass to no addition to the pulp component, and oxidized as a neutralizing agent. A paper-containing resin composition and an injection molded product for evaluation were obtained in the same manner except that magnesium (trade name: magnesium oxide: manufactured by Tomita Pharmaceutical Co., Ltd.) was changed from 1.5% by mass to no additive with respect to the total mass. .

  The laminated waste paper used in Examples 1 to 4 and Comparative Examples 1 to 3, the obtained paper pulverized product, the paper-containing resin composition, and the evaluation injection molded product were evaluated by the following methods, and the results are shown in Table 1. Indicated.

<Paper ratio>
The ratio of the paper in the paper-containing resin composition is indicated as the paper ratio, and here, the total amount of paper and fillers such as calcium carbonate is defined as the paper material.

<MFR>
Measured according to ASTM D1238-04c, “Standard Test Method for Flow Rates of Thermoplastics by Extraction Plasometer”. Test temperature = 190 ° C., test load = 10 kg. It measured about the paper containing resin composition.

<Fiber dispersibility>
A predetermined amount of carbon black was blended with the paper-containing resin composition to produce an evaluation injection molded product, and the degree of fiber dispersion was evaluated according to the following criteria.
X: Many undispersed fibers, inferior to practical use.
Δ: Some undispersed fibers, slightly inferior and not practical.
○: No undispersed fiber, excellent.

<Moldability>
Workability at the time of molding processing for producing a molded product from the paper-containing resin composition was evaluated according to the following criteria.
X: The molded product was not obtained.
Δ: Formability is poor and cannot be practically used.
○: Good formability.

<Discoloration>
The molded product was judged based on the following criteria based on visual sensation.
×: Obvious yellowish, inferior to practical use,
Δ: Slightly yellowish, inferior to practical use,
○: Excellent without yellow.

<Odor>
The odor of the molded product was determined according to the following criteria.
Δ: Slightly burnt odor, inferior to practical use
○: Excellent without odor.

<Tensile strength>
Measured according to JIS K 7113: 1995 “Plastic Tensile Test Method”.

<Bending strength>
Measured according to JIS K 7203: 1995 “Bending test method of hard plastic”.

<IZOD (Izod impact strength)>
Measured according to ASTM D256-04 “Test Methods for Determination of the Pendulum Impact Resistance of Notched Specimens of Plastics” (no notch).

<Water absorption rate>
Measured according to JIS K 7209: 2000 “Plastics—How to Obtain Water Absorption” Method D.

  In Examples 1 and 2, a paper-containing resin composition was prepared using milk carton printing trimming waste having NBKP of 90% by mass of the base film of polyethylene film laminated paper. All of the paper-containing resin compositions had good fiber dispersibility and moldability because they could be uniformly dispersed by esterification of the pulverized product and kneading by the twin screw extruder, despite the high NBKP content. The molded product obtained was neither discolored nor odorous.

  In Examples 3 and 4, a paper-containing resin composition was prepared using a recovered milk pack having an NBKP of 80% by mass as a base film of polyethylene film laminated paper. Despite having a high NBKP content, uniform dispersion was achieved by esterification of the pulverized product and kneading by a twin-screw extruder. Therefore, the fiber dispersibility and moldability were good, and the obtained molded product had discoloration and odor. There was not.

  In Comparative Example 1, the MFR value was 5 g / 10 min. However, since the pulverized particle size of the milk carton printing trimming waste was large, the dispersibility was insufficient and the fiber dispersibility and moldability were poor. Moreover, since the neutralizing agent was not added, the obtained molded product showed discoloration and odor.

  The mechanical strength, particularly tensile strength, bending strength, and water absorption were better in the examples than in the comparative examples.

Claims (14)

Containing at least a pulverized paper esterified with a polybasic acid anhydride, a polypropylene resin, a polyethylene resin and an alkaline earth metal compound;
The pulverized product and the polypropylene resin are main components,
A paper-containing resin composition having a melt mass flow rate (MFR) (test temperature = 190 ° C., test load = 10 kg) defined by ASTM-D1238-04c of 2.0 to 25.0 g / 10 min.   The polybasic acid anhydride is maleic anhydride, and the ratio of maleic anhydride introduced by esterification is 0.1 to 5% by mass with respect to the pulp component. The paper-containing resin composition described.   The paper-containing resin composition according to claim 1 or 2, wherein the alkaline earth metal compound is a magnesium compound and is contained in an amount of 0.1 to 5% by mass in terms of magnesium oxide based on the total mass. object.   The paper is a polyethylene film laminated paper based on a base paper containing 50% by mass or more of softwood bleached chemical pulp, and the polyethylene resin is derived from the polyethylene film laminated paper. The paper-containing resin composition according to 2 or 3.   The paper-containing resin composition according to claim 1, 2, 3, or 4, wherein a total amount of the paper material including the pulverized material and the filler is 51% by mass or more. Containing at least a pulverized paper esterified with a polybasic acid anhydride, a polypropylene resin, a polyethylene resin and an alkaline earth metal compound;
The pulverized product and the polypropylene resin are main components,
A paper-containing resin molded product having a melt mass flow rate (MFR) defined by ASTM-D1238-04c (test temperature = 190 ° C., test load = 10 kg) of 2.0 to 25.0 g / 10 min.   7. The paper according to claim 6, wherein the paper is a polyethylene film laminated paper based on a base paper containing 50% by mass or more of softwood bleached chemical pulp, and the polyethylene resin is derived from the polyethylene film laminated paper. The paper-containing resin molded article as described. A step of pulverizing a polyethylene film laminated paper based on a base paper containing 50% by weight or more of softwood bleached chemical pulp to obtain a pulverized paper,
Esterifying the pulverized product with a polybasic acid anhydride;
Neutralizing the organic acid with an alkaline earth metal compound;
At least the pulverized product and the polypropylene resin are kneaded by a twin screw extruder, and a melt mass flow rate (MFR) (test temperature = 190 ° C., test load = 10 kg) defined by ASTM-D1238-04c is 2.0 to 25. Obtaining a paper-containing resin composition that is 0.0 g / 10 min;
A method for producing a paper-containing resin composition, comprising:   The method for producing a paper-containing resin composition according to claim 8, wherein the pulverized product has a pulverized particle size of 0.5 to 2.5 mm.   The polyethylene film laminated paper is a polyethylene film laminated paper for a liquid container, cutting waste of the polyethylene film laminated paper, and / or recovered waste paper of the polyethylene film laminated paper. A method for producing a paper-containing resin composition. A step of pulverizing a polyethylene film laminated paper based on a base paper containing 50% by weight or more of softwood bleached chemical pulp to obtain a pulverized paper,
Esterifying the pulverized product with a polybasic acid anhydride;
Neutralizing the organic acid with an alkaline earth metal compound;
Kneading at least the pulverized product and polypropylene resin with a twin-screw extruder to obtain a paper-containing resin composition;
The paper-containing resin composition was molded by an injection molding machine, and the melt mass flow rate (MFR) (test temperature = 190 ° C., test load = 10 kg) defined by ASTM-D1238-04c was 2.0 to 25.0 g / Obtaining a paper-containing resin molded product that is 10 min;
A method for producing a paper-containing resin molded product, comprising:   The method for producing a paper-containing resin molded article according to claim 11, wherein the pulverized product has a pulverized particle size of 0.5 to 2.5 mm.   The polyethylene film laminated paper is a polyethylene film laminated paper for a liquid container, cutting waste of the polyethylene film laminated paper, and / or recovered waste paper of the polyethylene film laminated paper. A method for producing a paper-containing resin molded product. 14. The paper-containing resin molded article according to claim 11, wherein a fluidity improver is added in the step of obtaining the paper-containing resin composition and / or the step of obtaining the paper-containing resin molded article. Manufacturing method.