JP2007045863A - Paper-containing resin composition, its molding and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a paper-containing resin composition by reusing the whole of laminated paper much comprising bleached chemical pulp of needle-leaf tree of long fiber and having difficulty in reproduction and aiming effective utilization of resource, namely, a paper-containing resin composition that eliminates an undispersed material of paper, is uniformly mixed and dispersed by improving kneadability of a crushed material having a coarse particle diameter with a resin raw material without making ground paper into fine particle diameters, as a result, has improved moldability of injection molding, etc., even in increase of paper content by improving fluidity of paper-containing resin composition. <P>SOLUTION: The paper-containing resin composition comprises ground laminated paper composed of base paper containing at least ≥50 mass% of bleached chemical pulp of needle-leaf tree as a base and a resin and has 2.0-7.0 g/10min melt mass flow rate (MFR) (test temperature=190°C, test load=10kg) defined by ASTM-D1238-04c. <P>COPYRIGHT: (C)2007,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 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. It is related with the paper-containing resin composition which can increase the content rate 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 classified into pulverization (pulverizer and pulverized particle size), kneading with thermoplastic resin (mixing chemical and resin blending ratio), and proposals for granulation. The object is to improve the moldability by increasing the mixing and dispersion. It is known that the fluidity of the mixed composition of the resin and the 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) Or a method of using a finely pulverized 100-mesh pass after pulverizing polypropylene laminated waste paper to 3 mm square (see, for example, 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 melt mass flow rate (MFR) of pellet resin to 5-50. There is a method (for example, refer to Patent Document 6).

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

  In the method of reusing recycled laminated paper by wet method, it is necessary to separate the paper and the film, the yield of the recovered fiber is low, and further, the processing of incineration, landfill, etc. of the separated laminate film is required. Because of the necessity, a method for reusing the waste laminated paper as a whole has not been put into practical use.

  Each of the methods disclosed in Patent Documents 1, 2, and 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, the lower the melting efficiency, such as the relatively low melting point polyethylene contained in the plastic film laminated paper melts due to the heat generated during crushing, causing 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 the screen and the flat net are clogged due to the heat melting of the laminated resin. Problems such as contact between the fixed blade and the rotary blade due to temperature rise occur.

  In the present invention, the laminated paper mainly composed of the softwood bleached chemical pulp that specifies its configuration is high in paper strength, but the basis weight is high, both sides of the paper are coated with a resin layer such as thick polyethylene, and the rigidity is also high. It is difficult to pulverize. The reason why it is difficult to finely pulverize 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. For example, the pulverization efficiency is significantly reduced. Accordingly, it has been a challenge to establish a technique for improving the kneading and dispersibility of the pulverized laminate paper having a coarse particle size and the resin, and using a resin composition having a high paper blending ratio for injection molding or the like.

  The first object of the present invention is a laminate paper, which has been conventionally used only for incineration or fiber, and which contains a large amount of long-fiber softwood bleached chemical pulp such as printing cutting waste from liquid containers and collected liquid containers. Is to provide a paper-containing resin composition aiming at effective utilization of resources. In other words, without reducing the pulverized particle size of the laminated paper, by improving the kneadability of 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 provide a paper-containing resin molded article having a high content of laminated paper, no discoloration or odor, and excellent impact strength, using the paper-containing resin composition according to the present invention. It is in.

  The third object of the present invention is to provide a production method for obtaining a paper-containing resin composition that is uniformly mixed and dispersed without kneading of laminated paper 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 have intensively studied the relationship between the composition of the paper used for the pulverized paper and the pulverized paper, the workability when mixed with the resin, 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 and a resin containing 50% by mass or more of softwood bleached chemical pulp, and has a melt mass flow rate (MFR) defined by ASTM-D1238-04c (MFR) ( Test temperature = 190 ° C., test load = 10 kg) is 2.0 to 7.0 g / 10 min. Here, it is preferable that the paper is a laminated paper based on a base paper containing 50% by mass or more of softwood bleached chemical pulp.

  Moreover, in the paper containing resin composition which concerns on this invention, it is preferable that the average fiber length of the pulp contained in the paper containing resin composition contained in it is 0.3-2 mm. The problem of reduction in operability and efficiency of the pulverizer and the problem of decrease in fluidity during molding are less likely to occur.

  Moreover, it is preferable that the paper containing resin composition which concerns on this invention contains 0.1-5 mass% of fluidity improvers. There is no undispersed laminate paper and it is easy to mix and disperse uniformly. Granulation is easy, the occurrence of blooming and the deterioration of physical properties are suppressed, and a sufficient fluidity improvement effect is obtained.

  Moreover, in the paper containing resin composition which concerns on this invention, it is preferable that the total amount of the paper raw material containing the said ground material and filler is 51 mass% or more. It can be set as an environment-friendly paper-containing resin composition.

  The paper-containing resin molded product according to the present invention contains a pulverized paper product containing 50% by mass or more of softwood bleached chemical pulp, a resin, and a fluidity improver, and the content of the fluidity improver is 0.1 to 0.1%. 5 mass%, and melt mass flow rate (MFR) (test temperature = 190 ° C., test load = 10 kg) defined by ASTM-D1238-04c is 2.0 to 7.0 / 10 min. . Here, it is preferable that the paper is a laminated paper based on a base paper containing 50% by mass or more of softwood bleached chemical pulp.

  The method for producing a paper-containing resin composition according to the present invention comprises a step of pulverizing a laminate paper based on a base paper containing 50% by mass or more of softwood bleached chemical pulp to obtain a pulverized product, and at least the pulverized product and resin Containing a paper having a melt mass flow rate (MFR) defined by ASTM-D1238-04c (test temperature = 190 ° C., test load = 10 kg) of 2.0 to 7.0 g / 10 min. And a step of obtaining a resin composition.

  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.

  Moreover, in the manufacturing method of the paper containing resin composition which concerns on this invention, it is preferable that the said laminated paper is a laminated paper for paper containers, a cutting waste, or a collection waste paper. Increases the efficiency of effective use of resources.

  The method for producing a paper-containing resin molded product according to the present invention includes a step of pulverizing a base paper containing 50% by mass or more of softwood bleached chemical pulp to obtain a pulverized product, and at least the pulverized product and the resin Kneaded with a twin screw extruder to obtain a paper-containing resin composition, and a mixture containing the paper-containing resin mixture and a fluidity improver is molded by an injection molding machine, and is defined by ASTM-D1238-04c. And a step of obtaining a paper-containing resin molded product having a melt mass flow rate (MFR) (test temperature = 190 ° C., test load = 10 kg) of 2.0 to 7.0 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.

  Moreover, in the manufacturing method of the paper containing resin molded product which concerns on this invention, it is preferable that the said laminated paper is a laminated paper for paper containers, a cutting waste, or a collection waste paper. Increases the efficiency of effective use of resources.

  The paper-containing resin composition of the present invention, which has been conventionally used only for incineration or fiber content, is a hard-to-regenerate laminate that contains a large amount of soft fiber bleached chemical pulp of long fibers such as printing cutting waste from liquid containers and recovered liquid containers The entire paper is reused. That is, the paper-containing resin composition of the present invention improves the kneadability of 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, the flowability of the paper-containing resin composition is improved, so that 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 laminated paper, and is excellent in impact strength without discoloration or odor.

  In the method for producing a paper-containing resin composition of the present invention, a paper-containing resin composition in which the laminated paper is uniformly mixed and dispersed can be obtained by kneading using a twin screw extruder.

  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.

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

  The paper-containing resin composition according to the present embodiment includes at least a paper pulverized product and resin containing 50% by mass or more of softwood bleached chemical pulp (hereinafter abbreviated as “NBKP”), and ASTM-D1238-04c. The melt mass flow rate (hereinafter abbreviated as “MFR”) (test temperature = 190 ° C., test load = 10 kg) is 2.0 to 7.0 g / 10 min. The paper is a laminated paper based on a base paper containing 50% by mass or more of NBKP, or the base paper before lamination.

Laminated paper is obtained by laminating a resin having a film thickness of 20 to 50 μm on one side or both sides of a base paper. Here, the laminated paper is preferably laminated paper for liquid containers, cutting waste, or recovered waste paper. Increases the efficiency of effective use of resources. A typical example is a laminated paper for a liquid container called a so-called milk carton, or printed cutting waste (hereinafter referred to as “print trimming waste”) or recovered waste paper such as a milk pack (hereinafter collectively referred to as these). Called “laminated paper etc.”). 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 laminated paper is mainly 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. When the NBKP is less than 50% by mass, the strength suitability of the paper-containing resin composition of the present embodiment tends to be insufficient. Examples of the laminated film material include low-density polyethylene resin, high-density polyethylene resin, and polypropylene resin (hereinafter abbreviated as “PP resin”).

  A pulverized product is obtained by pulverizing the laminated paper. In addition, you may obtain a pulverized material by grind | pulverizing the base paper before lamination, or the thing which mixed the base paper with the laminate paper. 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 size 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 size”). 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 laminated with heat-meltable resin such as polyethylene, the smaller the pulverized particle size, the more likely the clogging of screens and flat nets due to heat melting of the resin occurs, 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, the operation of the pulverizer becomes extremely difficult particularly when pulverizing to a particle size of less than 0.5 mm. However, when the particle diameter 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.

  The resin used in this embodiment is a general-purpose resin such as polyethylene resin, polypropylene resin, polystyrene resin, acrylonitrile / butadiene / styrene resin, acrylonitrile / styrene resin, urethane resin, polyester resin, polycarbonate resin, or modified resins thereof. . These resins may be new synthetic products, pulverized products of used molded products, recycled products, or single or mixed products.

  In the paper-containing resin composition of the present embodiment, components other than the pulverized paper and the 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, in any case But it ’s okay. 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 addition amount of the fluidity improver 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 fluidity is insufficient, and if it exceeds 5% by mass, granulation tends to be difficult, and the physical properties of blooming, paper-containing resin composition and paper-containing resin molded product are deteriorated. There is a case. The fluidity improver is not particularly limited as long as it prevents heat generation due to friction during molding and increases the fluidity of the paper-containing resin composition. For example, polyethylene wax, low density polyethylene, stearic acid, zinc stearate Higher fatty acids such as 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 or calcium carbonate may be added.

  In the paper-containing resin composition according to the present embodiment, the total amount of the paper material including the pulverized paper 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. Since the treatment by the twin screw extruder can be made more uniform twice or more than once, it is preferable. At this time, it is more preferable to knead | mix at the temperature of 100-200 degreeC. Before kneading with a twin-screw extruder, the 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. The average fiber length of the pulp to be contained in the paper-containing resin composition thus obtained is in the range of 0.3 mm to 2 mm. It is preferable for preventing a decrease in the thickness. More preferably, it is 0.5-1.8 mm. It is preferable that not only NBKP but the average fiber length of all the pulps in the paper-containing resin composition fall within this range. If it is less than 0.3 mm, the operability and efficiency of the pulverizer are lowered, and if it exceeds 2 mm, the fluidity during molding becomes a problem. By controlling the pulverized particle size of the pulverized paper and the kneading conditions, a paper-containing resin composition having such an average fiber length can be obtained.

  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 7.0 g / 10 min. Preferably, it is 2.8 to 5.5 g / 10 min. 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. In the present embodiment containing a large amount of NBKP, when the pulverized paper and the resin are sufficiently dispersed, the MFR approaches 7.0 g / 10 min. This MFR value is not greatly affected by whether or not a fluidity improver is added when kneading with a twin screw extruder.

  As described above, the paper-containing resin composition according to this embodiment includes a step of pulverizing a base paper containing 50% by mass or more of NBKP to obtain a pulverized product, and at least two of the pulverized product and the resin. Kneading with a screw extruder to obtain a paper-containing resin composition having an MFR (test temperature = 190 ° C., test load = 10 kg) defined by ASTM-D1238-04c of 2.0 to 7.0 g / 10 min; It can obtain with the manufacturing method which has these. Note that the base paper before lamination may be used instead of the laminated paper, or the base paper may be added to the laminated paper.

  Next, the paper-containing resin molded product according to the present embodiment includes a step of pulverizing a laminate paper based on a base paper containing NBKP of 50% by mass or more to obtain a pulverized product, and at least the pulverized product and the resin are biaxial. A step of kneading with an extruder to obtain a paper-containing resin composition, a mixture containing the paper-containing resin mixture and a fluidity improver is molded by an injection molding machine, and MFR (as defined in ASTM-D1238-04c ( And a step of obtaining a paper-containing resin molded product having a test temperature of 190 ° C. and a test load of 10 kg) of 2.0 to 7.0 g / 10 min. Alternatively, the paper-containing resin molded product according to the present embodiment includes a step of pulverizing a laminate paper based on a base paper containing NBKP of 50% by mass or more to obtain a pulverized product, and at least the pulverized product, resin, and fluidity. A step of kneading the improver with a twin-screw extruder to obtain a paper-containing resin composition, and molding the paper-containing resin mixture with an injection molding machine, the MFR specified by ASTM-D1238-04c (test temperature = 190) And a step of obtaining a paper-containing resin molded product having a test load = 10 kg) of 2.0 to 7.0 g / 10 min. That is, the paper-containing resin molded product of the present embodiment is obtained by molding a paper-containing resin composition that contains a fluidity improver in advance, or a paper-containing resin composition that does not contain a fluidity improver. It can be obtained by adding a fluidity improver to the product and molding. Note that the base paper before lamination may be used instead of the laminated paper, or the base paper may be added to the laminated paper.

  The paper-containing resin molded product according to the present embodiment thus obtained contains a paper pulverized product containing 50% by mass or more of NBKP, a resin, and a fluidity improver, and the content of the fluidity improver. Is 0.1 to 5% by mass, and MFR (test temperature = 190 ° C., test load = 10 kg) defined by ASTM-D1238-04c is 2.0 to 7.0 g / 10 min. The MFR is more preferably 2.8 to 5.5 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 any method, the paper-containing resin molded body of the present embodiment contains 0.1 to 5% by mass of a fluidity improver. More preferably, it contains 0.5 to 3% by mass.

  In the paper-containing resin molded product of this embodiment, the contained laminate paper is a laminate paper for liquid containers, cutting waste, or recovered waste paper, and resources are effectively used. Moreover, the average fiber length of a pulp is 0.3-2 mm, and is the same as a paper containing resin composition. Moreover, it is preferable that the total amount of the paper raw 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 paper-containing resin molded products include dishes, cups, bowls, spoons, and combs.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated more concretely, this 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 contains 90% by mass of NBKP, grinds milk carton printing trimming waste with a basis weight of 393 g / m ² , a thickness of 0.48 mm, and a density of 0.82 g / cm ³ (models BO-2575 and HaA-2542: (Made by Horai Co., Ltd.) and passed through a 0.5 mmφ screen to obtain a crushed paper.
[Production of paper-containing resin composition]
Subsequently, titanium oxide (trade name: Typaque A-220: manufactured by Ishihara Sangyo Co., Ltd.), modified PP resin (trade name: Umex 1010: manufactured by San Nopco) and PP resin (trade name: J-5051HP: Idemitsu Petrochemical Co., Ltd.) Made of erucic acid amide (trade name Alflow P-10: manufactured by Nippon Oil & Fats Co., Ltd.) as a fluidity improver in an amount of 0.5% by mass with respect to the total mass, and uniformly mixed with a Henschel mixer, Thereafter, it was 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 number of passing treatments of the twin screw extruder was set to once. The paper ratio in this paper-containing resin composition was 55% by mass. Moreover, the average fiber length of the pulp in this paper-containing resin composition was 0.4 mm.
[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 having a cylinder setting temperature of 180 ° C.

(Example 2)
A paper-containing resin composition and an evaluation injection-molded article were obtained in the same manner as in Example 1 except that the screen was changed from a 0.5 mmφ screen to a 1.0 mmφ screen in the production of the pulverized paper. The paper ratio in this paper-containing resin composition was 55% by mass. Moreover, the average fiber length of the pulp in this paper-containing resin composition was 0.8 mm.

(Example 3)
The pulverized paper was produced in the same manner as in Example 2.
[Production of paper-containing resin composition]
Next, titanium oxide (trade name: Typaque A-220: manufactured by Ishihara Sangyo Co., Ltd.), modified PP resin (trade name: Umex 1010: manufactured by San Nopco) and PP resin (trade name: J-5051HP: Idemitsu Petrochemical Co., Ltd.) And then uniformly mixed with a Henschel mixer, and then put into a pelleter (model F-60: manufactured by Fuji Powder Co., Ltd.) and a twin screw extruder to form a pellet, thereby obtaining a paper-containing resin composition. The number of passing treatments of the twin screw extruder was set to once. The paper ratio in this paper-containing resin composition was 55% by mass. Moreover, the average fiber length of the pulp in this paper-containing resin composition was 0.8 mm.
[Manufacture of injection molded products for evaluation]
To the above-mentioned paper-containing resin composition, erucic acid amide (trade name Alflow P-10: manufactured by NOF Corporation) is added as a fluidity improver in an amount of 0.5% by mass with respect to the total mass, and the cylinder set temperature is 180. An injection molded product for evaluation was produced using an injection molding machine at 0 ° C.

Example 4
In the manufacture of the pulverized paper, the raw material of the pulverized paper was from the milk carton printing trimming waste used in Example 1, and the base paper contained 80% by mass of NBKP, the basis weight was 362 g / m ² , the thickness was 0.47 mm, A paper-containing resin composition and an injection molded product for evaluation were used in the same manner as in Example 1 except that the collected milk pack was changed to a density of 0.78 g / cm ³ and the screen was changed from a 0.5 mmφ screen to a 2.0 mmφ screen. Got. The paper ratio in this paper-containing resin composition was 55% by mass. Moreover, the average fiber length of the pulp in this paper-containing resin composition was 1.7 mm.

(Example 5)
In the production of the paper-containing resin composition, the blended amount of the paper pulverized product is changed from the amount at which the paper ratio in the paper-containing resin composition is 55% by mass to 60% by mass in the paper-containing resin composition. The amount of fluidity improver added is changed from 0.5% by mass to 1.0% by mass with respect to the total mass, A paper-containing resin composition and an evaluation injection-molded article were obtained in the same manner as in Example 4 except that the number of pass treatments was changed from 1 to 2 times. Moreover, the average fiber length of the pulp in this paper-containing resin composition was 1.7 mm.

(Example 6)
In the production of the paper-containing resin composition, the screen was changed from a 0.5 mmφ screen to a 2.0 mmφ screen, and the blended amount of the pulverized paper was such that the paper ratio in the paper-containing resin composition was 55% by mass. From the amount, the paper ratio in the paper-containing resin composition is changed to an amount that becomes 60% by mass, and the addition amount of the fluidity improver is changed from the amount that becomes 0.5% by mass to the total mass, to the total mass. The paper-containing resin composition and the evaluation injection molded article were evaluated in the same manner as in Example 1 except that the amount was changed to 1.0% by mass and the number of passing treatments of the twin-screw extruder was changed from 1 to 2 times. Obtained. Moreover, the average fiber length of the pulp in this paper-containing resin composition was 1.7 mm.

(Comparative Example 1)
A paper-containing resin composition and an evaluation injection-molded article were obtained in the same manner as in Example 1 except that the screen was changed from a 0.5 mmφ screen to a 3.0 mmφ screen in the production of the pulverized paper. The paper ratio in this paper-containing resin composition was 55% by mass. The average fiber length of the pulp in this paper-containing resin composition was 2.2 mm.

(Comparative Example 2)
In the production of the paper-containing resin composition, the blended amount of the paper pulverized product is changed from the amount at which the paper ratio in the paper-containing resin composition is 55% by mass to 45% by mass in the paper-containing resin composition. A paper-containing resin composition and an evaluation injection-molded product were obtained in the same manner as in Example 2 except that the treatment with the twin-screw extruder was untreated. The average fiber length of the pulp in this paper-containing resin composition was 0.8 mm.

(Comparative Example 3)
In the production of the paper-containing resin composition, a paper-containing resin composition and an evaluation injection-molded article were obtained in the same manner as in Example 2 except that the treatment by the twin screw extruder was not treated. The paper ratio in this paper-containing resin composition was 55% by mass. The average fiber length of the pulp in this paper-containing resin composition was 0.8 mm.

(Comparative Example 4)
In the production of the paper-containing resin composition, the addition amount of the fluidity improver was changed from 0.5% by mass to the total mass to 1.0% by mass with respect to the total mass. A paper-containing resin composition and an evaluation injection-molded article were obtained in the same manner as in Example 2 except that the treatment by the extruder was not treated. The paper ratio in this paper-containing resin composition was 55% by mass. The average fiber length of the pulp in this paper-containing resin composition was 0.8 mm.

(Comparative Example 5)
In the production of the paper-containing resin composition, the blended amount of the paper pulverized product is changed from the amount at which the paper ratio in the paper-containing resin composition is 55% by mass to 60% by mass in the paper-containing resin composition. The amount of the fluidity improver added is changed from 0.5% by mass to the total mass to 2.0% by mass with respect to the total mass, and by a twin screw extruder. A paper-containing resin composition and an injection molded product for evaluation were obtained in the same manner as in Example 2 except that the treatment was untreated. The average fiber length of the pulp in this paper-containing resin composition was 0.8 mm.

(Comparative Example 6)
In the production of the pulverized paper, the raw material of the pulverized paper was changed from the milk carton printing trimming waste used in Example 2 to 40% by weight of NBKP and a basis weight of 260 g / m ² cup paper. In the production of the paper-containing resin composition, the addition amount of the fluidity improver was changed from 0.5% by mass to 2.0% by mass with respect to the total mass, and 2%. A paper-containing resin composition and an evaluation injection-molded article were obtained in the same manner as in Example 2 except that the treatment by the shaft extruder was not treated. The paper ratio in this paper-containing resin composition was 55% by mass. Moreover, the average fiber length of the pulp in this paper-containing resin composition was 0.8 mm.

(Comparative Example 7)
[Manufacture of crushed paper]
A base paper containing 0% by mass of NBKP and a basis weight of 170 g / m ² of resin-coated photographic paper base paper (without protective gelatin layer and photosensitive emulsion layer) is pulverized (models BO-2575 and HaA-2542): (Made by Horai Co., Ltd.) and passed through a 0.3 mmφ screen to obtain a crushed paper. The manufacture of the paper-containing resin composition and the evaluation injection-molded product were carried out in the same manner as in Comparative Example 6 to obtain the paper-containing resin composition and the evaluation injection-molded product. The paper ratio in this paper-containing resin composition was 55% by mass. Moreover, the average fiber length of the pulp in this paper-containing resin composition was 0.2 mm.

  Evaluation of the obtained paper pulverized product, paper-containing resin composition and evaluation injection-molded product such as the laminated paper used in Examples 1 to 6 and Comparative Examples 1 to 7 was performed by the following method, and the results are shown in Table 1. It was shown to.

<Average fiber length>
After the paper-containing resin composition was extracted with hot xylene, the remaining pulp content was determined with a Kajaani fiber length measuring device (model Fiber Lab: manufactured by Valmet Automation).

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

<Moldability>
The workability at the time of molding processing for producing a molded product from a paper-containing resin composition was evaluated according to the following criteria.
Δ: Formability is poor,
○: Good formability.

<Discoloration>
Judgment of molded products based on the following criteria.
X: Clear yellowish, inferior
Δ: Slightly yellowish, inferior,
○: No yellow body and excellent.

<Odor>
The odor of the molded product is judged according to the following criteria.
Δ: Slightly burnt odor, inferior,
○: 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”.

<Bending elastic modulus>
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 Determining of the Pendulum Impact Resistance of Notched Specimens of Plastics” (no notch).

<HDT (deflection temperature under load)>
Measured according to ASDM D648-04 “Standard Test Method for Deformation Temperature of Plastics Under Flexural Load in the Edge Position”.

  In Examples 1 and 2, a paper-containing resin composition was prepared using milk carton printing trimming waste having a NBKP of 90% by mass as a base paper. All of the paper-containing resin compositions were uniformly dispersible by kneading with a twin screw extruder despite the high NBKP content, so that the moldability was good. There wasn't.

  In Example 3, similarly to Examples 1 and 2, a paper-containing resin composition was prepared using milk carton printing trimming waste having a NBKP of 90% by mass of base paper. The paper-containing resin composition did not contain a fluidity improver, and a fluidity improver was added during molding to obtain a molded product. Despite the high content of NBKP, it could be uniformly dispersed by kneading in a twin-screw extruder, and the effect of the fluidity improver was fully demonstrated even when added during molding, so the moldability is good. The obtained molded product was free from discoloration and odor.

  In Example 4, a paper-containing resin composition was prepared using a recovered milk pack having a base paper NBKP of 80% by mass. Despite the high content of NBKP, uniform dispersion was achieved by kneading with a twin-screw extruder, so that the moldability was good, and the obtained molded article was free from discoloration and odor.

  In Examples 5 and 6, the number of pass treatments of the twin screw extruder was set to 2 times. Compared with Examples 1, 2, 3 and 4, the average fiber length of the pulp is long and the paper ratio is high, but despite the high NBKP content, it can be uniformly dispersed by kneading in a twin screw extruder. Therefore, all of Examples 5 and 6 had good moldability, and the obtained molded article had neither discoloration nor odor.

  Since Comparative Examples 1, 2, 3, 4 and 5 were not kneaded by a twin screw extruder, the MFR value was 1.8 g / 10 min or less, and the dispersibility is considered insufficient. As a result, the moldability was poor. In Example 2, the twin screw extruder was processed, and in Comparative Example 3, the twin screw extruder was not processed. The tensile strength, bending strength, and IZOD, which are mechanical strengths, were lower in Comparative Example 3 than in Example 2. Since it was uniformly dispersed by kneading with a twin screw extruder, the mechanical strength was improved.

  In Comparative Example 6, a cup paper having an NBKP content of less than 50% by mass was used, and in Comparative Example 7, a paper-containing resin composition was prepared using a photographic paper base paper containing no NBKP. In either case, since the NBKP content was small, IZOD was low, and a molded product having sufficient mechanical strength could not be obtained.

  The thermal strength was almost the same between the example and the comparative example, but the mechanical strength, particularly the tensile strength, bending strength and IZOD were better in the example than in the comparative example.

Claims (13)

  At least melt mass flow rate (MFR) defined by ASTM-D1238-04c (test temperature = 190 ° C., test load = 10 kg), containing pulverized paper and resin containing 50% by mass or more of softwood bleached chemical pulp Is a paper-containing resin composition, characterized by being 2.0 to 7.0 g / 10 min.   The paper-containing resin composition according to claim 1, wherein the paper is a laminated paper based on a base paper containing 50% by mass or more of softwood bleached chemical pulp.   The paper-containing resin composition according to claim 1 or 2, wherein an average fiber length of the pulp contained in the paper-containing resin composition is 0.3 to 2 mm.   The paper-containing resin composition according to claim 1, 2 or 3, which contains 0.1 to 5% by mass of a fluidity improver.   5. The paper-containing resin composition according to claim 1, wherein the total amount of the paper material including the pulverized material and the filler is 51% by mass or more.   A paper pulverized product containing 50% by mass or more of softwood bleached chemical pulp, a resin and a fluidity improver are contained, the content of the fluidity improver is 0.1 to 5% by mass, and ASTM-D1238-04c. A paper-containing resin-molded product characterized in that the melt mass flow rate (MFR) (test temperature = 190 ° C., test load = 10 kg) defined by the above is 2.0 to 7.0 g / 10 min.   The paper-containing resin molded article according to claim 6, wherein the paper is a laminated paper based on a base paper containing 50% by mass or more of softwood bleached chemical pulp. Crushing a laminated paper based on a base paper containing 50% by mass or more of softwood bleached chemical pulp to obtain a pulverized product;
At least the pulverized product and the resin are kneaded by a twin screw extruder, and the melt mass flow rate (MFR) (test temperature = 190 ° C., test load = 10 kg) defined by ASTM-D1238-04c is 2.0 to 7. And a step of obtaining a paper-containing resin composition that is 0 g / 10 min.   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 method for producing a paper-containing resin composition according to claim 8 or 9, wherein the laminated paper is laminated paper for a liquid container, cutting waste, or recovered waste paper. Crushing a laminated paper based on a base paper containing 50% by mass or more of softwood bleached chemical pulp to obtain a pulverized product;
At least a step of kneading the pulverized product and the resin with a twin screw extruder to obtain a paper-containing resin composition;
The paper-containing resin mixture and a mixture containing a fluidity improver are molded by an injection molding machine, and melt mass flow rate (MFR) defined by ASTM-D1238-04c (test temperature = 190 ° C., test load = 10 kg). And a step of obtaining a paper-containing resin molded product having a thickness of 2.0 to 7.0 g / 10 min.   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 method for producing a paper-containing resin molded product according to claim 11 or 12, wherein the laminated paper is laminated paper for a liquid container, cutting waste, or recovered waste paper.