Method for producing cellulose-containing resin additive and method for producing cellulose-containing master batch as well as method for producing cellulose composite resin molded product

Abstract

To provide a method for producing a cellulose-containing resin additive that is used for obtaining a cellulose composite resin molded product in which a cellulose raw material is uniformly dispersed in a resin raw material in a simple and efficient way.SOLUTION: A method for producing cellulose-containing resin additives used in the production of cellulose composite resin molded products (H1), comprises a cellulose swelling process (S1) in which a solvent is added to unsolved cellulose raw material to obtain a cellulose swollen material, and a shearing process (S2) in which the thermoplastic resin raw material consisting of polyolefin with a weight average molecular weight of 160,000 or less is mixed with the cellulose swollen material and subjected to solid-phase shearing under a temperature range where the solvent's boiling point is not exceeded and the thermoplastic resin raw material does not melt.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a cellulose-containing resin additive, a method for producing a cellulose-containing masterbatch, and a method for producing a cellulose composite resin molded product, and in particular to a cellulose-containing resin additive used in the production of a cellulose composite resin molded product, a method for producing a cellulose-containing masterbatch using the cellulose-containing resin additive, and a method for producing a cellulose composite resin molded product. [Background technology]

[0002] In recent years, the United Nations has set international goals for sustainable development called Sustainable Development Goals (SDGs), and one of these environmental issues is the reduction of plastic usage. Efforts are being made to solve climate change by reducing the use of petroleum-based plastics, thereby reducing GHG emissions.

[0003] In the field of resin products, cellulose composite resins, which are made by mixing cellulose raw materials obtained from plant raw materials with resin raw materials, have been actively researched and developed as an approach to environmental issues. By uniformly dispersing the cellulose raw materials in the resin raw materials, the cellulose raw materials act as reinforcing materials for the resin, improving the strength, elasticity, etc. of the resin molded products. Therefore, cellulose composite resins are expected to be environmentally friendly fiber-reinforced resins, and demand is increasing.

[0004] However, in the above-mentioned cellulose composite resin, it is not easy to uniformly disperse the hydrophilic cellulose raw material in the hydrophobic resin raw material such as polyolefin resin, and if the cellulose raw material is not uniformly dispersed in the resin raw material, it may actually result in a decrease in the strength of the resin molded product.

[0005] In order to solve such problems, methods for uniformly dispersing hydrophilic cellulose raw materials in resin raw materials have been studied. Examples of such methods include a method in which plant fibers (cellulose raw materials) such as paper pulp are coated with wax particles to make the plant fiber surface hydrophobic (Patent Document 1), and a method in which hydrophobic polymers are bonded to the hydroxyl groups of the cellulose raw materials via reactive groups (Patent Document 2).

[0006] According to the method of Patent Document 1, the surface of the plant fiber becomes hydrophobic, which makes it easier to disperse the plant fiber in the resin. Also, according to the method of Patent Document 2, a cellulose composite formed by binding a hydrophobic polymer to the hydroxyl groups of the cellulose raw material can be uniformly dispersed in a non-polar resin without adding a compatibilizer (dispersant).

[0007] However, in these methods, the cellulose raw material is used in a state containing a large amount of moisture, and therefore it takes a long time to dry the moisture remaining in the cellulose composite resin, which raises concerns that problems such as reduced productivity and increased production costs may occur. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 5708657 [Patent Document 2] International Publication No. 2021 / 075224 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in consideration of the above points, and provides a method for producing a cellulose-containing resin additive used to obtain a cellulose composite resin molded product in which a cellulose raw material is uniformly dispersed in a resin raw material simply and efficiently, a method for producing a cellulose-containing masterbatch using the cellulose-containing resin additive, and a method for producing a cellulose composite resin molded product. [Means for solving the problem]

[0010] That is, the first invention relates to a method for producing a cellulose-containing resin additive used in the production of cellulose composite resin moldings, comprising a cellulose swelling step in which a solvent is added to an undefibrated cellulose raw material to obtain a cellulose swollen material in which the cellulose raw material is swelled, and a shearing step in which a thermoplastic resin raw material that is a polyolefin having a weight-average molecular weight of 160,000 or less and the cellulose swellable material are mixed and solid-phase sheared at a temperature range below the boiling point of the solvent and in which the thermoplastic resin raw material does not melt, wherein in the shearing step, the thermoplastic resin raw material is broken down into a particulate resin material, and the cellulose swellable material is defibrated into defibrated cellulose, and the particulate resin material further penetrates between the fibers of the defibrated cellulose to obtain a cellulose-containing resin additive.

[0011] A second invention relates to a method for producing a cellulose-containing resin additive according to the first invention, wherein the thermoplastic resin raw material contains an acid-modified polyolefin.

[0012] A third invention relates to a method for producing a cellulose-containing resin additive according to the first or second invention, wherein the solvent is water.

[0013] A fourth invention relates to the method for producing a cellulose-containing resin additive according to the first or second invention, wherein the average fiber diameter of the cellulose raw material is 10 to 40 μm.

[0014] A fifth invention relates to the method for producing a cellulose-containing resin additive according to the third invention, wherein the average fiber diameter of the cellulose raw material is 10 to 40 μm.

[0015] The sixth invention relates to a method for producing a cellulose-containing masterbatch, comprising a cellulose-containing masterbatch molding step in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive of the first or second invention is heated, kneaded, and molded to obtain a cellulose-containing masterbatch.

[0016] The invention of claim 7 relates to a method for producing a cellulose-containing masterbatch, comprising a cellulose-containing masterbatch molding step in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive of the third invention is heated, kneaded, and molded to obtain a cellulose-containing masterbatch.

[0017] The eighth invention relates to a method for producing a cellulose-containing masterbatch, comprising a cellulose-containing masterbatch molding step in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive of the fourth invention is heated, kneaded, and molded to obtain a cellulose-containing masterbatch.

[0018] The ninth invention relates to a method for producing a cellulose-containing masterbatch, comprising a cellulose-containing masterbatch molding step in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive of the fifth invention is heated, kneaded, and molded to obtain a cellulose-containing masterbatch.

[0019] The tenth invention relates to a method for producing a cellulose composite resin molded product, comprising a cellulose composite resin molding step (S4) in which the cellulose-containing masterbatch obtained by the cellulose-containing masterbatch manufacturing method of the sixth invention is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product.

[0020] The eleventh invention relates to a method for producing a cellulose composite resin molded product, comprising a cellulose composite resin molding step (S4) in which the cellulose-containing masterbatch obtained by the cellulose-containing masterbatch manufacturing method of the seventh invention is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product.

[0021] The twelfth invention relates to a method for producing a cellulose composite resin molded product, comprising a cellulose composite resin molding step (S4) in which the cellulose-containing masterbatch obtained by the cellulose-containing masterbatch manufacturing method of the eighth invention is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product.

[0022] The thirteenth invention relates to a method for producing a cellulose composite resin molded product, comprising a cellulose composite resin molding step (S4) in which the cellulose-containing masterbatch obtained by the method for producing a cellulose-containing masterbatch of the ninth invention is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product.

[0023] The fourteenth invention relates to a method for producing a cellulose composite resin molded product, comprising a cellulose composite resin molding step (S5) in which the cellulose-containing resin additive obtained by the cellulose-containing resin additive manufacturing method of the first or second invention is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product.

[0024] The fifteenth invention relates to a method for producing a cellulose composite resin molded product, comprising a cellulose composite resin molding step (S5) in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive of the third invention is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product.

[0025] The sixteenth invention relates to a method for producing a cellulose composite resin molded product, comprising a cellulose composite resin molding step (S5) in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive of the fourth invention is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product.

[0026] The 17th invention relates to a method for producing a cellulose composite resin molded product, comprising a cellulose composite resin molding step (S5) in which the cellulose-containing resin additive obtained by the cellulose-containing resin additive manufacturing method of the fifth invention is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product. Effect of the Invention

[0027] According to the first aspect of the present invention, there is provided a method for producing a cellulose-containing resin additive used in the production of a cellulose composite resin molding, the method comprising: a cellulose swelling step in which a solvent is added to an undefibrated cellulose raw material to obtain a cellulose swollen material in which the cellulose raw material is swelled; and a shearing step in which a thermoplastic resin raw material that is a polyolefin having a weight-average molecular weight of 160,000 or less and the cellulose swellable material are mixed and solid-phase sheared at a temperature range below the boiling point of the solvent and in which the thermoplastic resin raw material does not melt. In the shearing step, the thermoplastic resin raw material is broken down into a particulate resin material, and the cellulose swellable material is defibrated into defibrated cellulose. The particulate resin material further penetrates between the fibers of the defibrated cellulose to obtain a cellulose-containing resin additive. This makes it possible to simply and efficiently produce a cellulose-containing resin additive used to obtain a cellulose composite resin molding in which the cellulose raw material is uniformly dispersed in the thermoplastic resin raw material.

[0028] According to the second invention, the method for producing a cellulose-containing resin additive of the first invention, the thermoplastic resin raw material contains an acid-modified polyolefin, so that the thermoplastic resin raw material and the cellulose raw material are more strongly bonded to each other.

[0029] According to the method for producing a cellulose-containing resin additive of the third invention, since the solvent is water in the first or second invention, the cellulose swelling material can be easily produced.

[0030] According to the method for producing a cellulose-containing resin additive of the fourth invention, in the first or second invention, the average fiber diameter of the cellulose raw material is 10 to 40 μm, so that the function as a reinforcing material can be appropriately imparted.

[0031] According to the method for producing a cellulose-containing resin additive of the fifth invention, in the third invention, since the average fiber diameter of the cellulose raw material is 10 to 40 μm, it is possible to appropriately impart the function as a reinforcing material.

[0032] According to the sixth aspect of the present invention, the method for producing a cellulose-containing masterbatch includes a cellulose-containing masterbatch molding step in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive according to the first or second aspect of the present invention is heated, kneaded, and molded to obtain a cellulose-containing masterbatch, so that a cellulose-containing masterbatch in which a cellulose raw material is uniformly dispersed in a thermoplastic resin raw material can be produced simply and efficiently. In addition, by carrying out the cellulose-containing masterbatch molding step following the production of the cellulose-containing resin additive, a cellulose-containing masterbatch can be efficiently produced from the cellulose-containing resin additive. Furthermore, the cellulose-containing masterbatch produced can be molded (pelletized) by removing moisture, which improves ease of handling during storage, etc.

[0033] According to the seventh invention, the method for producing a cellulose-containing masterbatch includes a cellulose-containing masterbatch molding step in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive according to the third invention is heated, kneaded, and molded to obtain a cellulose-containing masterbatch, so that a cellulose-containing masterbatch in which a cellulose raw material is uniformly dispersed in a thermoplastic resin raw material can be produced simply and efficiently. In addition, by carrying out the cellulose-containing masterbatch molding step following the production of the cellulose-containing resin additive, a cellulose-containing masterbatch can be efficiently produced from the cellulose-containing resin additive. Furthermore, the produced cellulose-containing masterbatch can be molded (pelletized) by removing moisture, which improves ease of handling during storage, etc.

[0034] According to the eighth aspect of the present invention, the method for producing a cellulose-containing masterbatch includes a cellulose-containing masterbatch molding step in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive according to the fourth aspect of the present invention is heated, kneaded, and molded to obtain a cellulose-containing masterbatch, so that a cellulose-containing masterbatch in which a cellulose raw material is uniformly dispersed in a thermoplastic resin raw material can be produced simply and efficiently. In addition, by carrying out the cellulose-containing masterbatch molding step following the production of the cellulose-containing resin additive, a cellulose-containing masterbatch can be efficiently produced from the cellulose-containing resin additive. Furthermore, the produced cellulose-containing masterbatch can be molded (pelletized) by removing moisture, which improves ease of handling during storage, etc.

[0035] According to the ninth aspect of the present invention, the cellulose-containing masterbatch manufacturing method includes a cellulose-containing masterbatch molding step in which the cellulose-containing resin additive obtained by the cellulose-containing resin additive manufacturing method of the fifth aspect of the present invention is heated, kneaded, and molded to obtain a cellulose-containing masterbatch, so that a cellulose-containing masterbatch in which a cellulose resin raw material is uniformly dispersed in a thermoplastic resin raw material can be easily and efficiently manufactured. In addition, by carrying out the cellulose-containing masterbatch molding step following the manufacture of the cellulose-containing resin additive, a cellulose-containing masterbatch can be efficiently manufactured from the cellulose-containing resin additive. Furthermore, the cellulose-containing masterbatch manufactured can be molded (pelletized) by removing moisture, which improves ease of handling during storage, etc.

[0036] The method for producing a cellulose composite resin molded product of the tenth aspect of the present invention includes a cellulose composite resin molding step (S4) in which the cellulose-containing masterbatch obtained by the method for producing a cellulose-containing masterbatch of the sixth aspect of the present invention is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product. This makes it possible to easily and efficiently produce a cellulose composite resin molded product in which the cellulose raw material is uniformly dispersed in the thermoplastic resin raw material.

[0037] The method for producing a cellulose composite resin molded product of the eleventh invention includes a cellulose composite resin molding step (S4) in which the cellulose-containing masterbatch obtained by the method for producing a cellulose-containing masterbatch of the seventh invention is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product. This makes it possible to easily and efficiently produce a cellulose composite resin molded product in which the cellulose raw material is uniformly dispersed in the thermoplastic resin raw material.

[0038] The method for producing a cellulose composite resin molded product of the 12th invention includes a cellulose composite resin molding step (S4) in which the cellulose-containing masterbatch obtained by the method for producing a cellulose-containing masterbatch of the eighth invention is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product. Therefore, a cellulose composite resin molded product in which the cellulose raw material is uniformly dispersed in the thermoplastic resin raw material can be produced simply and efficiently.

[0039] The method for producing a cellulose composite resin molded product of the thirteenth invention includes a cellulose composite resin molding step (S4) in which the cellulose-containing masterbatch obtained by the method for producing a cellulose-containing masterbatch of the ninth invention is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product. This makes it possible to easily and efficiently produce a cellulose composite resin molded product in which the cellulose raw material is uniformly dispersed in the thermoplastic resin raw material.

[0040] According to the method for producing a cellulose composite resin molded product of the fourteenth aspect of the present invention, since it includes a cellulose composite resin molding step (S5) in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive of the first or second aspect of the present invention is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product, it is possible to simply and efficiently produce a cellulose composite resin molded product in which the cellulose raw material is uniformly dispersed in the thermoplastic resin raw material. In particular, it is possible to directly produce a cellulose composite resin molded product from the cellulose-containing resin additive.

[0041] According to the method for producing a cellulose composite resin molded product of the fifteenth aspect of the present invention, the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive of the third aspect of the present invention is added to a polyolefin resin raw material, and the cellulose composite resin molded product is obtained by heating and kneading the cellulose-containing resin additive and molding the cellulose composite resin molded product (S5). Therefore, the cellulose composite resin molded product in which the cellulose raw material is uniformly dispersed in the thermoplastic resin raw material can be produced simply and efficiently. In particular, the cellulose composite resin molded product can be produced directly from the cellulose-containing resin additive.

[0042] According to the method for producing a cellulose composite resin molded product of the 16th invention, since the method includes a cellulose composite resin molding step (S5) in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive of the 4th invention is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product, it is possible to simply and efficiently produce a cellulose composite resin molded product in which the cellulose raw material is uniformly dispersed in the thermoplastic resin raw material. In particular, the cellulose composite resin molded product can be directly produced from the cellulose-containing resin additive.

[0043] According to the method for producing a cellulose composite resin molded product of the seventeenth aspect of the present invention, since the method includes a cellulose composite resin molding step (S5) in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive of the fifth aspect of the present invention is added to a polyolefin resin raw material, and the cellulose composite resin molded product is obtained by heating and kneading the cellulose-containing resin additive and molding the polyolefin resin raw material, the cellulose composite resin molded product in which the cellulose raw material is uniformly dispersed in the thermoplastic resin raw material can be produced simply and efficiently. In particular, the cellulose composite resin molded product can be produced directly from the cellulose-containing resin additive. [Brief description of the drawings]

[0044] [Figure 1] FIG. 1 is a schematic process diagram of a method for producing a cellulose-containing resin additive according to one embodiment of the present invention. [Diagram 2] 2 is an enlarged photograph of a cellulose-containing resin additive (Prototype 1-) obtained by the production method of FIG. 1. [Diagram 3] FIG. 1 is a schematic process diagram of a method for producing a cellulose-containing masterbatch according to one embodiment of the present invention. [Figure 4] FIG. 1 is a schematic process diagram of a method for producing a cellulose composite resin molded product according to one embodiment of the present invention. [Diagram 5] FIG. 2 is a schematic process diagram of a method for producing a cellulose composite resin molded product according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] The manufacturing method (H1) of a cellulose-containing resin additive according to one embodiment of the present invention shown in FIG. 1 is a method for manufacturing an additive used in manufacturing a cellulose composite resin molded product, and includes a cellulose swelling step (S1) and a shearing step (S2). The cellulose-containing resin additive obtained by the manufacturing method (H1) of the present invention is in a powder form and is used as a reinforcing material for a cellulose composite resin molded product. Examples of the cellulose composite resin molded product include resin products such as housings for home appliances, building parts, and interior parts for automobiles.

[0046] The cellulose swelling step (S1) is a step in which the cellulose raw material is immersed in a solvent to obtain a swollen cellulose material in which the cellulose raw material is swollen. The cellulose raw material is a material used as a reinforcing material to improve the strength, elasticity, etc. of resin molded products. Pulp is used as the cellulose raw material. Examples of cellulose raw materials include paper pulp, which is a raw material in which the purity of the cellulose component is increased by crushing wood and removing impurities such as lignin, and cotton linter pulp, which is made by removing impurities from cotton and increasing the purity of the cellulose component. These pulps have a high purity of the cellulose component and are preferable as cellulose raw materials for the purpose of reinforcing resin molded products.

[0047] The cellulose raw material is preferably unfibrillated and has an average fiber diameter of about 10 to 40 μm. Cellulose raw materials obtained from plant raw materials have an average fiber diameter of up to about 40 μm. If the average fiber diameter is too small, the contribution of the cellulose raw material to the strength and elasticity of the cellulose composite resin molded product after molding may be small.

[0048] The solvent is a material that swells the cellulose raw material, and for example, water, isopropanol, dimethyl sulfoxide, etc. can be used, and water is particularly preferable. By using water as the solvent, a cellulose swelling material containing water and the cellulose raw material can be easily produced. The mixing ratio of the unfibrillated cellulose raw material and the solvent is preferably about 50 to 1000 parts by weight added to 100 parts by weight of the unfibrillated cellulose raw material. The amount of the solvent is not particularly limited, but considering the efficiency of swelling of the cellulose raw material and the processing efficiency in the shearing step (S2) described later, it is preferable to add 65 to 900 parts by weight to 100 parts by weight of the cellulose raw material, that is, the solid content concentration of the cellulose raw material is 10 to 60%. The mixed material of the cellulose raw material and the solvent is prepared by applying the solvent to the cellulose raw material or immersing the cellulose raw material in the solvent. If the amount of the solvent added is too small, the swelling of the cellulose raw material may be insufficient. If too much solvent is added, the clay particles will become too small during solid-state shearing, making it difficult to apply shear, which may result in a decrease in the defibration efficiency of the cellulose raw material (cellulose-swelling material).

[0049] The shearing process (S2) is a process in which the cellulose swollen material obtained in the cellulose swelling process (S1) is mixed with a thermoplastic resin raw material and subjected to solid-state shearing, in which the swollen undefibrated cellulose raw material (cellulose swollen material) is defibrated to obtain a cellulose-containing resin additive in which the cellulose raw material is uniformly dispersed in the thermoplastic resin raw material.

[0050] The thermoplastic resin raw material is a material that holds the defibrated cellulose raw material in a substantially uniformly dispersed state. As the thermoplastic resin raw material, it is preferable to use one that has good affinity with the cellulose raw material, for example, acid-modified polyolefin. The acid-modified polyolefin has a hydrophilic group that ensures good affinity with the cellulose raw material and a hydrophobic group that ensures good affinity with the thermoplastic resin (polyolefin). Therefore, the thermoplastic resin raw material and the cellulose raw material are more firmly bonded to each other.

[0051] Solid-phase shearing is a process in which a mixture of a cellulose swelling material and a thermoplastic resin raw material is sheared in a solid state. Specifically, the mixture of the cellulose swelling material and the thermoplastic resin raw material is sheared below the boiling point of the solvent and in a temperature range in which the thermoplastic resin raw material does not melt. In the shearing process, the cellulose raw material swollen with the solvent and the thermoplastic resin raw material are sheared as solids in a temperature range in which the thermoplastic resin raw material does not melt. By making the temperature of the solvent below the boiling point during solid-phase shearing, the cellulose raw material is appropriately swollen by water without volatilizing the solvent (water), and appropriate shear can be applied to the cellulose raw material during solid-phase shearing. This makes it possible to defibrate the cellulose raw material in a more swollen state, making it easier for the cellulose raw material to be defibrated and more efficiently compounded with the thermoplastic resin raw material.

[0052] A problem that has been encountered in the past is that since the cellulose raw material is hydrophilic, it is not easy to uniformly disperse it in a hydrophobic thermoplastic resin raw material such as a polyolefin resin. If the cellulose raw material is not uniformly dispersed in the thermoplastic resin raw material, the strength of the cellulose composite resin molded product after molding may be reduced. Therefore, the inventors have conducted extensive research into a method for uniformly dispersing the hydrophilic cellulose raw material in the hydrophobic thermoplastic resin raw material. As a result, the inventors have found that when the cellulose raw material and the thermoplastic resin raw material are compounded for use in the manufacture of a cellulose composite resin molded product, the molecular weight of the thermoplastic resin raw material is reduced to a certain degree, and the cellulose raw material and the low molecular weight thermoplastic resin raw material are subjected to solid-phase shearing, thereby defibrating the cellulose raw material and uniformly dispersing it in the thermoplastic resin raw material.

[0053] That is, the thermoplastic resin raw material used when mixing with the cellulose swelling material and shearing it must be a low molecular weight polyolefin having a weight average molecular weight capable of penetrating between the fibers of the cellulose raw material. The weight average molecular weight is known as one of the indicators of average molecular weight used to grasp the properties of polymers. The low molecular weight polyolefin is a polyolefin having a weight average molecular weight of tens of thousands or less, and the polyolefin used as the thermoplastic resin raw material in the present invention is specified as having a weight average molecular weight of 160,000 or less capable of penetrating between the fibers of the cellulose raw material. The thermoplastic resin raw material is preferably added in an amount of 10 to 1,000 parts by weight per 100 parts by weight of the cellulose raw material. More preferably, 20 to 500 parts by weight, and even more preferably, 25 to 400 parts by weight are added.

[0054] In the shearing process, the thermoplastic resin raw material is broken down into a particulate form by solid-phase shearing to form a particulate resin material. Since the thermoplastic resin raw material has a small molecular weight, it is easily broken down, and when it is mixed with the cellulose swelling material and sheared in the solid phase, it acts like a bead mill, and it is considered that the cellulose swelling material is more easily defibrated. The particulate form includes those with an average particle diameter of about 50 to 1000 μm. In addition, the cellulose swelling material is defibrated by solid-phase shearing to form defibrated cellulose. At that time, the particulate resin material penetrates between the fibers of the cellulose swelling material and shearing is performed, so it is considered that the defibration of the cellulose swelling material is promoted by the particulate resin material, and the cellulose raw material (defibrated cellulose) is dispersed in the thermoplastic resin raw material (particulate resin material). Then, the particulate resin material further penetrates between the fibers of the defibrated cellulose, and a cellulose-containing resin additive in which the cellulose raw material (defibrated cellulose) is approximately uniformly dispersed in the thermoplastic resin raw material (particulate resin material) is obtained. The cellulose-containing resin additive thus obtained has a form in which the particulate resin material and the defibrated cellulose are integrated together, as shown in the enlarged photograph of FIG.

[0055] In the above-mentioned manufacturing method (H1) of the cellulose-containing resin additive of the present invention, since the thermoplastic resin raw material, which is a polyolefin having a weight-average molecular weight of 160,000 or less, can penetrate between the fibers of the cellulose raw material, it is considered to be beneficial that the thermoplastic resin raw material can be subdivided by solid-phase shearing. The thermoplastic resin raw material can be used in the form of pellets, flakes, particles, powder, etc., but from the viewpoint of ease of handling, etc., it is preferable to use a pelletized form such as a cylindrical shape. However, it is considered that the pelletized thermoplastic resin raw material is difficult to penetrate between the fibers when its size is large compared to the size of the gap between the fibers of the cellulose raw material. Therefore, in the present invention, it is considered that the thermoplastic resin raw material is subdivided in parallel with the cellulose swelling material being defibrated by solid-phase shearing, so that the fine particle-shaped resin material can efficiently penetrate between the fibers of the defibrated cellulose to disperse the cellulose raw material in the resin raw material.

[0056] Furthermore, in the manufacturing method (H1) of the cellulose-containing resin additive of the present invention, a cellulose raw material having an average fiber diameter of 10 to 40 μm is preferably used. If the average fiber diameter of the cellulose raw material is too small, the cellulose raw material may become too fine due to solid-phase shearing, which may cause aggregation of the cellulose raw material and reduce the contribution of the cellulose raw material to the strength and elasticity of the cellulose composite resin molded product after molding. Therefore, by using a cellulose raw material having the above average fiber diameter, the cellulose-containing resin additive can be appropriately imparted with the function of a reinforcing material.

[0057] Next, the method for producing a cellulose-containing masterbatch (H2) according to one embodiment of the present invention shown in FIG. 3 will be described. The method for producing a cellulose-containing masterbatch (H2) of the present invention is a method for producing a masterbatch used in producing a cellulose composite resin molded product using the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive (H1), and includes a cellulose-containing masterbatch molding step (S3). The cellulose-containing masterbatch obtained by the production method (H2) of the present invention is used as an additive for cellulose in a cellulose composite resin molded product or as a substrate. The cellulose-containing masterbatch is preferably used, for example, when pelletized or flaked, because it is easy to handle.

[0058] The cellulose-containing masterbatch molding step (S3) is a step in which the cellulose-containing resin additive is heated, kneaded, and molded to obtain a cellulose-containing masterbatch. The heating and kneading is performed in a kneader such as a twin-screw kneading extruder at a temperature range of the melting point of the thermoplastic resin raw material + 10°C or more. When the temperature during heating and kneading is in this temperature range, the water (solvent) contained in the cellulose-containing resin additive can be removed and the cellulose-containing masterbatch can be molded efficiently. In addition, the cellulose-containing masterbatch is formed into an appropriate form by the molding step (S3), and is preferably pelletized or flaked from the viewpoint of ease of handling, etc.

[0059] In the cellulose-containing masterbatch production method (H2) of the present invention, the cellulose-containing resin additive that is heated and kneaded is a thermoplastic resin raw material that has penetrated between the fibers of defibrated cellulose, and therefore, by using the cellulose-containing resin additive in the production of a cellulose-containing masterbatch, a cellulose-containing masterbatch in which the cellulose raw material is uniformly dispersed in the thermoplastic resin raw material can be produced simply and efficiently. Furthermore, the cellulose-containing masterbatch produced by the cellulose-containing masterbatch production method (H2) can be molded (pelletized) by removing moisture by heating and kneading in the cellulose-containing masterbatch molding step (S3), improving ease of handling during storage, etc.

[0060] In the cellulose-containing masterbatch manufacturing method (H2), the cellulose-containing resin additive used can be an appropriate additive manufactured by the cellulose-containing resin additive manufacturing method (H1). For example, a cellulose-containing resin additive previously manufactured by the cellulose-containing resin additive manufacturing method (H1) may be used. The cellulose-containing resin additive is inexpensive because it requires fewer steps, but it is in powder form and may be difficult to handle during transportation and use.

[0061] Therefore, as shown in Fig. 3, it is advantageous in terms of handling to carry out the cellulose-containing masterbatch molding step (S3) immediately after the cellulose-containing resin additive manufacturing method (H1) including the cellulose swelling step (S1) and the shearing step (S2). Since the heating and kneading (cellulose-containing masterbatch molding step (S3)) is carried out immediately after the shearing step (S2) of the cellulose-containing resin additive manufacturing method (H1), the treatment step can be carried out regardless of the handling of the cellulose-containing resin additive, and the cellulose-containing masterbatch can be efficiently manufactured from the cellulose-containing resin additive.

[0062] Next, a description will be given of the method (H3) for producing a cellulose composite resin molded product according to one embodiment of the present invention shown in Fig. 4. The method (H3) for producing a cellulose composite resin molded product of the present invention is a method for producing a cellulose composite resin molded product using the cellulose-containing masterbatch obtained by the method (H2) for producing a cellulose-containing masterbatch, and includes a cellulose composite resin molding step (S4).

[0063] The cellulose composite resin molding step (S4) (hereinafter referred to as the first cellulose composite resin molding step (S4)) is a step in which a cellulose-containing masterbatch is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product.

[0064] Polyethylene resins, polypropylene resins, etc. are used as polyolefin resin raw materials. It is preferable to use a polyolefin resin with a weight average molecular weight larger than that of the thermoplastic resin used in the shearing process, since it is easier to mold. If the weight average molecular weight of the polyolefin resin raw material is too small, the toughness of the resin molded product will be low, and if the weight average molecular weight is too large, the viscosity will be high and molding of the resin molded product may be difficult. For example, polypropylene for injection molding has a weight average molecular weight of approximately 250,000, and polyethylene has a weight average molecular weight of approximately 45,000. Considering the strength, moldability, and application of the resin molded product, the type and weight average molecular weight of the polyolefin resin raw material used are appropriately selected.

[0065] In the heat kneading, it is preferable to mold the cellulose composite resin molded product in a kneader such as a twin-screw kneading extruder at a temperature range of the melting point of the polyolefin resin raw material + 10 ° C or more. When the temperature during heat kneading is in this temperature range, a cellulose composite resin molded product in which the cellulose-containing master batch and the polyolefin resin raw material are uniformly mixed can be obtained. In this cellulose composite resin molded product, almost no aggregates formed by aggregation due to hydrogen bonds of cellulose fibers remain, and the cellulose fibers are uniformly dispersed in the resin raw material, so that the reinforcing effect of the cellulose fibers is effectively exerted. In addition, it is preferable to use an acid-modified polyolefin when manufacturing the cellulose master batch used in the cellulose composite resin molding step (S4). The acid-modified polyolefin has a hydrophilic group that ensures good affinity with the cellulose raw material and a hydrophobic group that ensures good affinity with the polyolefin resin raw material. Therefore, the polyolefin resin raw material and the cellulose raw material are firmly bonded to each other, which contributes to improving the strength of the cellulose composite resin molded product.

[0066] The cellulose-containing masterbatch used in the manufacturing method (H3) for such a cellulose composite resin molded product is one in which the cellulose raw material is uniformly dispersed in the thermoplastic resin raw material. For this reason, in the manufacturing method (H3) for a cellulose composite resin molded product of the present invention, the cellulose-containing masterbatch is added to the polyolefin resin raw material and heated and kneaded without using any special kneading treatment or additives in the first cellulose composite resin molding step (S4), and thus a cellulose composite resin molded product in which the cellulose raw material is uniformly dispersed in the thermoplastic resin raw material can be easily and efficiently manufactured.

[0067] In addition, the manufacturing method (H3) for a cellulose composite resin molded product may be a first cellulose composite resin molding step (S4) carried out continuously from the manufacturing method (H2) for a cellulose-containing masterbatch. Here, since the cellulose-containing masterbatch is in a form suitable for storage, transportation, etc., the cellulose composite resin molded product can be easily manufactured even if the first cellulose composite resin molding step (S4) is carried out using a cellulose-containing masterbatch separately manufactured by the manufacturing method (H2) for a cellulose-containing masterbatch. Therefore, the method can be particularly preferably carried out in cases where the step (S3) for manufacturing the cellulose-containing masterbatch and the step (S4) for molding the cellulose composite resin molded product are carried out in different facilities, etc.

[0068] Meanwhile, the method (H4) for producing a cellulose composite resin molded product according to another embodiment of the present invention shown in FIG. 5 is a method for producing a resin molded product using the cellulose-containing resin additive obtained by the method (H1) for producing a cellulose-containing resin additive, and includes a cellulose composite resin molding step (S5).

[0069] The cellulose composite resin molding step (S5) (hereinafter referred to as the second cellulose composite resin molding step (S5)) is a step in which a cellulose-containing resin additive is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product. As with the resin raw material used in the first cellulose composite resin molding step (S4), an appropriate resin molded product is selected and used according to the application. In the heat kneading in the second cellulose composite resin molding step (S5), it is preferable to mold the cellulose composite resin molded product in a kneader such as a twin-screw kneading extruder at a temperature range of the melting point of the polyolefin resin raw material + 10 ° C. or more. When the temperature during heat kneading is in this temperature range, the moisture (solvent) contained in the cellulose-containing resin additive can be removed and the cellulose-containing resin additive and the polyolefin resin raw material can be mixed uniformly. In addition, when an acid-modified polyolefin is used in the production of a cellulose masterbatch used in the cellulose composite resin molding step (S5), it contributes to improving the strength of the cellulose composite resin molded product, as in the case of using the acid-modified polyolefin in the first cellulose composite resin molding step (S4).

[0070] In the manufacturing method (H4) of the cellulose composite resin molded product of the present invention, the cellulose-containing resin additive added to the polyolefin resin raw material and heated and kneaded is a particulate resin material that has penetrated between the fibers of the defibrated cellulose. Therefore, by using the cellulose-containing resin additive in the manufacture of the cellulose composite resin molded product, it is possible to simply and efficiently manufacture a cellulose composite resin molded product in which the cellulose raw material is uniformly dispersed in the thermoplastic resin raw material.

[0071] In addition, in the manufacturing method (H4) for the cellulose composite resin molded product, the second cellulose composite resin molding step (S5) is carried out continuously from the manufacturing method (H1) for the cellulose-containing resin additive. Therefore, unlike the manufacturing method (H3) for the cellulose composite resin molded product shown in Fig. 4, the cellulose composite resin molded product can be directly manufactured from the steps (S1-S2) for manufacturing the cellulose-containing resin additive without using a cellulose-containing master batch, and the cellulose composite resin molded product can be manufactured more efficiently. Therefore, the manufacturing method (H4) for the cellulose composite resin molded product is suitable for the case where the steps for manufacturing the cellulose composite resin molded product from raw materials such as cellulose and resin are continuously carried out in the same facility, etc. EXAMPLES

[0072] [Preparation of cellulose-containing resin additives] The following cellulose raw material, solvent, and resin raw material were used as raw materials in a predetermined blending ratio, and the solvent was added to the cellulose raw material to obtain a cellulose swelling material. The cellulose swelling material and the resin raw material were mixed, and solid-phase shearing was performed for about 3 minutes using a twin-screw kneading extruder (manufactured by Japan Steel Works, Ltd., "TEX25αIII") under conditions of Q / Ns = 0.005 and a cylinder temperature of 10°C to produce cellulose-containing resin additives (A1 to A13) of prototypes 1-1 to 1-13. The blending ratios of the raw materials for each prototype 1-1 to 1-13 are shown in Table 1 below.

[0073] [Cellulose raw material] C1: Cellulose raw material (Canfor, "CA-KP", derived from softwood pulp, average fiber diameter 35 μm) The average fiber diameter of the cellulose raw material was measured by the following method. Distilled water was added to the cellulose raw material to prepare a cellulose dispersion with a solid content concentration of 1%. The dispersion was observed at a magnification of 100 times using a digital microscope (manufactured by Keyence Corporation, "VHX-7000"), and the widths of 50 cellulose fibers were measured and the average value was taken as the average fiber diameter (microscopy method).

[0074] [solvent] S1: Distilled water

[0075] [Resin raw material] M1: Thermoplastic resin raw material (Clariant, polypropylene resin "PP6102", weight average molecular weight 3800) M2: Thermoplastic resin raw material (Sanyo Chemical Industries, Ltd., polypropylene resin "Viscol (registered trademark) 660-P", weight average molecular weight 10,000) M3: Thermoplastic resin raw material (Sanyo Chemical Industries, Ltd., polypropylene resin "Viscol (registered trademark) 550-P", weight average molecular weight 15,000) M4: Thermoplastic resin raw material (Sanyo Chemical Industries, Ltd., maleic anhydride modified polypropylene "UMEX (registered trademark) 1010", weight average molecular weight 30000, acid value 52 mg KOH / g) M5: Thermoplastic resin raw material (Sanyo Chemical Industries, Ltd., polypropylene resin "Viscol (registered trademark) 330-P", weight average molecular weight 40,000) M6: Thermoplastic resin raw material (RIKEN VITAMIN Co., Ltd., maleic anhydride modified polypropylene "RIKEAID (registered trademark) MG-670P", weight average molecular weight 153000, acid value 21 mgKOH / g) M7: Thermoplastic resin raw material (Japan Polypropylene Corporation, homopolypropylene "MA04A", weight average molecular weight 250,000) M8: Thermoplastic resin raw material (Japan Polypropylene Corporation, homopolypropylene "Novatec (registered trademark) FL100A", weight average molecular weight 510,000)

[0076] [Prototype example 1-1] Prototype Example 1-1 is a cellulose-containing resin additive (A1) prepared by blending 20 parts by mass of C1 as a cellulose raw material, 60 parts by mass of S1 as a solvent, and 20 parts by mass of M1 as a resin raw material.

[0077] [Prototype example 1-2] Prototype 1-2 is a cellulose-containing resin additive (A2) produced under the same conditions as Prototype 1-1, except that the resin raw materials of Prototype 1-1 were changed to 10 parts by mass of M2 and 10 parts by mass of M4.

[0078] [Prototype example 1-3] Prototype Example 1-3 is a cellulose-containing resin additive (A3) prepared by blending 23 parts by mass of C1 as a cellulose raw material, 67 parts by mass of S1 as a solvent, 5 parts by mass of M2 as resin raw materials, and 5 parts by mass of M4.

[0079] [Prototype example 1-4] Prototype Example 1-4 is a cellulose-containing resin additive (A4) prepared by blending 24 parts by mass of C1 as a cellulose raw material, 70 parts by mass of S1 as a solvent, 3 parts by mass of M2 as resin raw materials, and 3 parts by mass of M4.

[0080] [Prototype example 1-5] Prototype Example 1-5 is a cellulose-containing resin additive (A5) prepared by blending 44 parts by mass of C1 as a cellulose raw material, 44 parts by mass of S1 as a solvent, 6 parts by mass of M2 as resin raw materials, and 6 parts by mass of M4.

[0081] [Prototype example 1-6] Trial Example 1-6 is a cellulose-containing resin additive (A6) produced under the same conditions as Trial Example 1-1, except that the resin raw material M1 in Trial Example 1-1 was changed to M3.

[0082] [Prototype example 1-7] Prototype Example 1-7 is a cellulose-containing resin additive (A7) produced under the same conditions as Prototype Example 1-6, except that the resin raw materials of Prototype Example 1-6 were changed to 10 parts by mass of M3 and 10 parts by mass of M4.

[0083] [Prototype example 1-8] Trial Example 1-8 is a cellulose-containing resin additive (A8) produced under the same conditions as Trial Example 1-1, except that the resin raw material M1 in Trial Example 1-1 was changed to M4.

[0084] [Prototype example 1-9] Trial Example 1-9 is a cellulose-containing resin additive (A9) produced under the same conditions as Trial Example 1-1, except that the resin raw material M1 in Trial Example 1-1 was changed to M5.

[0085] [Prototype example 1-10] Prototype Example 1-10 is a cellulose-containing resin additive (A10) produced under the same conditions as Prototype Example 1-1, except that the resin raw material M1 in Prototype Example 1-1 was changed to M6.

[0086] [Prototype example 1-11] Prototype Example 1-11 is a cellulose-containing resin additive (A11) produced under the same conditions as Prototype Example 1-1, except that the resin raw material M1 in Prototype Example 1-1 was changed to M7.

[0087] [Prototype example 1-12] Prototype Example 1-12 is a cellulose-containing resin additive (A12) produced under the same conditions as Prototype Example 1-1, except that the resin raw material M1 in Prototype Example 1-1 was changed to M8.

[0088] [Prototype example 1-13] Prototype Example 1-13 is a cellulose-containing resin additive (A13) produced under the same conditions as Prototype Example 1-1, except that the resin raw materials of Prototype Example 1-1 were changed to 16 parts by mass of M2 and 4 parts by mass of M7.

[0089] [Table 1]

[0090] [Preparation of cellulose-containing masterbatch] Next, cellulose-containing masterbatches (B1 to B14) of prototype examples 2-1 to 2-14 were produced under the following conditions. The blending ratios of the raw materials for each of prototype examples 2-1 to 2-14 are shown in Table 2 below.

[0091] [Prototype example 2-1] Prototype example 2-1 is a cellulose-containing master batch (B1) prepared in pellet form by using the cellulose-containing resin additive A1 as a molding material and heating and kneading for about 5 minutes while removing moisture using the twin-screw kneading extruder under conditions of Q / Ns = 0.01 and a cylinder temperature of 160°C. The blending ratio of prototype example 2-1 is 50 parts by mass of cellulose raw material C1 and 50 parts by mass of resin raw material M1, due to the removal of moisture (solvent S1) from the cellulose-containing resin additive A1.

[0092] [Prototype example 2-2] Prototype example 2-2 is a cellulose-containing masterbatch (B2) produced under the same conditions as prototype example 2-1, except that the cellulose-containing resin additive A2 was used as the molding material and the blending ratio was changed to 50 parts by mass of cellulose raw material C1, 25 parts by mass of resin raw materials M2, and 25 parts by mass of M4.

[0093] [Prototype example 2-3] Prototype example 2-3 is a cellulose-containing masterbatch (B3) produced under the same conditions as prototype example 2-1, except that the cellulose-containing resin additive A3 was used as the molding material and the blending ratio was changed to 70 parts by mass of cellulose raw material C1, 15 parts by mass of resin raw materials M2, and 15 parts by mass of M4.

[0094] [Prototype example 2-4] Prototype example 2-4 is a cellulose-containing masterbatch (B4) produced under the same conditions as prototype example 2-1, except that cellulose-containing resin additive A4 was used as the molding material and the blending ratio was changed to 80 parts by mass of cellulose raw material C1, 10 parts by mass of resin raw materials M2, and 10 parts by mass of M4.

[0095] [Prototype example 2-5] Prototype example 2-5 is a cellulose-containing masterbatch (B5) produced under the same conditions as prototype example 2-1, except that cellulose-containing resin additive A5 was used as the molding material and the blending ratio was changed to 80 parts by mass of cellulose raw material C1, 10 parts by mass of resin raw materials M2, and 10 parts by mass of M4.

[0096] [Prototype Example 2-6] Prototype Example 2-6 is a cellulose-containing masterbatch (B6) produced under the same conditions as Prototype Example 2-1, except that cellulose-containing resin additive A6 was used as the molding material, and the cellulose raw material C1 was changed to 50 parts by mass, and the resin raw material M3 was changed to 50 parts by mass.

[0097] [Prototype Example 2-7] Prototype example 2-7 is a cellulose-containing masterbatch (B7) produced under the same conditions as prototype example 2-1, except that cellulose-containing resin additive A7 was used as the molding material and the blending ratio was changed to 50 parts by mass of cellulose raw material C1, 25 parts by mass of resin raw materials M3, and 25 parts by mass of M4.

[0098] [Prototype Example 2-8] Prototype example 2-8 is a cellulose-containing masterbatch (B8) produced under the same conditions as prototype example 2-1, except that cellulose-containing resin additive A8 was used as the molding material and the blending ratio was changed to 50 parts by mass of cellulose raw material C1 and 50 parts by mass of resin raw material M4.

[0099] [Prototype Example 2-9] Prototype Example 2-9 is a cellulose-containing master batch (B9) produced under the same conditions as Prototype Example 2-1, except that the cellulose-containing resin additive A9 was used as the molding material and the blending ratio was changed to 50 parts by mass of cellulose raw material C1 and 50 parts by mass of resin raw material M5.

[0100] [Prototype Example 2-10] Prototype Example 2-10 is a cellulose-containing master batch (B10) produced under the same conditions as Prototype Example 2-1, except that the cellulose-containing resin additive A10 was used as the molding material, the blending ratio was changed to 50 parts by mass of cellulose raw material C1 and 50 parts by mass of resin raw material M6, and the cylinder temperature was changed to 170°C.

[0101] [Prototype Example 2-11] Prototype Example 2-11 is a cellulose-containing master batch (B11) produced under the same conditions as Prototype Example 2-10, except that the cellulose-containing resin additive A11 was used as the molding material and the blending ratio was changed to 50 parts by mass of cellulose raw material C1 and 50 parts by mass of resin raw material M7.

[0102] [Prototype Example 2-12] Prototype Example 2-12 is a cellulose-containing master batch (B12) produced under the same conditions as Prototype Example 2-10, except that the cellulose-containing resin additive A12 was used as the molding material and the blending ratio was changed to 50 parts by mass of cellulose raw material C1 and 50 parts by mass of resin raw material M8.

[0103] [Prototype Example 2-13] Prototype Example 2-13 is a cellulose-containing master batch (B13) produced under the same conditions as Prototype Example 2-10, except that the cellulose-containing resin additive A13 was used as the molding material, and the blending ratio was changed to 50 parts by mass of cellulose raw material C1, 40 parts by mass of resin raw materials M3, and 10 parts by mass of M7.

[0104] [Prototype Example 2-14] Prototype Example 2-14 is a cellulose-containing master batch (B14) that is produced in the form of pellets by mixing 20 parts by mass of cellulose raw material C1, 60 parts by mass of solvent S1, and 20 parts by mass of resin raw material M3 without using a cellulose-containing resin additive as a molding material, and by heating and kneading for about 5 minutes while removing moisture using the twin-screw kneading extruder under conditions of Q / Ns = 0.01 and a cylinder temperature of 160 ° C. The mixing ratio of Prototype Example 2-14 is 50 parts by mass of cellulose raw material C1 and 50 parts by mass of resin raw material M3 because the moisture (solvent S1) has been removed.

[0105] [Table 2]

[0106] [Preparation of cellulose composite resin moldings] Furthermore, cellulose composite resin molded products of Prototype Examples 3-1 to 3-16 were produced under the following conditions. The blending ratios of the raw materials of each of Prototype Examples 3-1 to 3-16 are shown in Table 3 below.

[0107] [Prototype example 3-1] Prototype example 3-1 is a cellulose composite resin molding produced in the form of pellets by dry blending 20 parts by mass of cellulose-containing master batch B1 and 80 parts by mass of resin raw material M8 using the molding materials, and heat-kneading the mixture for about 5 minutes using the twin-screw kneading extruder under conditions of Q / Ns=0.05 and a cylinder temperature of 170° C. The blending ratio of prototype example 3-1 is 10 parts by mass of cellulose raw material C1, 10 parts by mass of resin raw material M1, and 80 parts by mass of resin raw material M8.

[0108] [Prototype example 3-2] Prototype 3-2 is a cellulose composite resin molded product produced under the same conditions as Prototype 3-1, except that the cellulose-containing master batch was changed to B2. The blending ratio of Prototype 3-2 is 10 parts by mass of cellulose raw material C1, 5 parts by mass of resin raw material M2, 5 parts by mass of resin raw material M4, and 80 parts by mass of resin raw material M8.

[0109] [Prototype example 3-3] Prototype 3-3 is a cellulose composite resin molded product produced under the same conditions as Prototype 3-1, except that the cellulose-containing master batch was changed to 14 parts by mass of B3 and 86 parts by mass of resin raw material M8. The blending ratio of Prototype 3-3 is 10 parts by mass of cellulose raw material C1, 2 parts by mass of resin raw material M2, 2 parts by mass of resin raw material M4, and 86 parts by mass of resin raw material M8.

[0110] [Prototype example 3-4] Prototype Example 3-4 is a cellulose composite resin molded product produced under the same conditions as Prototype Example 3-1, except that the cellulose-containing master batch was changed to 12 parts by mass of B4 and 88 parts by mass of resin raw material M8. The blending ratio of Prototype Example 3-4 is 10 parts by mass of cellulose raw material C1, 1 part by mass of resin raw material M2, 1 part by mass of resin raw material M4, and 88 parts by mass of resin raw material M8.

[0111] [Prototype example 3-5] Prototype 3-5 is a cellulose composite resin molded product produced under the same conditions as Prototype 3-1, except that the cellulose-containing master batch was changed to 12 parts by mass of B5 and 88 parts by mass of resin raw material M8. The blending ratio of Prototype 3-5 is 10 parts by mass of cellulose raw material C1, 1 part by mass of resin raw material M2, 1 part by mass of resin raw material M4, and 88 parts by mass of resin raw material M8.

[0112] [Prototype example 3-6] Prototype Example 3-6 is a cellulose composite resin molded product produced under the same conditions as Prototype Example 3-1, except that the cellulose-containing master batch was changed to B6. The blending ratio of Prototype Example 3-6 is 10 parts by mass of cellulose raw material C1, 10 parts by mass of resin raw material M3, and 80 parts by mass of resin raw material M8.

[0113] [Prototype example 3-7] Prototype 3-7 is a cellulose composite resin molded product produced under the same conditions as Prototype 3-1, except that the cellulose-containing master batch was changed to B7. The blending ratio of Prototype 3-7 is 10 parts by mass of cellulose raw material C1, 5 parts by mass of resin raw material M3, 5 parts by mass of resin raw material M4, and 80 parts by mass of resin raw material M8.

[0114] [Prototype example 3-8] Prototype 3-8 is a cellulose composite resin molded product produced under the same conditions as Prototype 3-1, except that the cellulose-containing master batch was changed to B8. The blending ratio of Prototype 3-8 is 10 parts by mass of cellulose raw material C1, 10 parts by mass of resin raw material M4, and 80 parts by mass of resin raw material M8.

[0115] [Prototype example 3-9] Prototype Example 3-9 is a cellulose composite resin molded product produced under the same conditions as Prototype Example 3-1, except that the cellulose-containing master batch was changed to B9. The blending ratio of Prototype Example 3-9 is 10 parts by mass of cellulose raw material C1, 10 parts by mass of resin raw material M5, and 80 parts by mass of resin raw material M8.

[0116] [Prototype example 3-10] Prototype Example 3-10 is a cellulose composite resin molded product produced under the same conditions as Prototype Example 3-1, except that the cellulose-containing master batch was changed to B10. The blending ratio of Prototype Example 3-10 is 10 parts by mass of cellulose raw material C1, 10 parts by mass of resin raw material M6, and 80 parts by mass of resin raw material M8.

[0117] [Prototype example 3-11] Prototype Example 3-11 is a cellulose composite resin molded product produced under the same conditions as Prototype Example 3-1, except that the cellulose-containing master batch was changed to B11. The blending ratio of Prototype Example 3-11 is 10 parts by mass of cellulose raw material C1, 10 parts by mass of resin raw material M7, and 80 parts by mass of resin raw material M8.

[0118] [Prototype example 3-12] Trial Example 3-12 is a cellulose composite resin molded product produced under the same conditions as Trial Example 3-1, except that the cellulose-containing master batch was changed to B12. The blending ratio of Trial Example 3-11 is 10 parts by mass of cellulose raw material C1 and 90 parts by mass of resin raw material M8.

[0119] [Prototype example 3-13] Prototype 3-13 is a cellulose composite resin molded product produced under the same conditions as Prototype 3-1, except that the cellulose-containing master batch was changed to B13. The blending ratio of Prototype 3-13 is 10 parts by mass of cellulose raw material C1, 8 parts by mass of resin raw material M2, 2 parts by mass of resin raw material M7, and 80 parts by mass of resin raw material M8.

[0120] [Prototype example 3-14] Prototype Example 3-14 is a cellulose composite resin molded product produced under the same conditions as Prototype Example 3-1, except that the cellulose-containing master batch was changed to B14. The blending ratio of Prototype Example 3-14 is 10 parts by mass of cellulose raw material C1, 10 parts by mass of resin raw material M3, and 80 parts by mass of resin raw material M8.

[0121] [Prototype example 3-15] Prototype Example 3-15 is a cellulose composite resin molded product produced under the same conditions as Prototype Example 3-1 except that the cellulose-containing resin additive A2 was added without using a cellulose-containing masterbatch, and the moisture was removed. The blending ratio of Prototype Example 3-15 is 10 parts by mass of cellulose raw material C1, 5 parts by mass of resin raw material M2, 5 parts by mass of resin raw material M4, and 80 parts by mass of resin raw material M8.

[0122] [Prototype example 3-16] Prototype example 3-16 is a resin (blank) containing no cellulose, and contains 100 parts by mass of resin raw material M8.

[0123] [Table 3]

[0124] The cellulose composite resin molded products of Prototype Examples 3-1 to 3-16 were measured for the coarse cellulose area ratio, the number of aggregates of the cellulose raw material contained in the cellulose composite resin molded products, and tensile properties (tensile strength, tensile modulus), and the measurement results are shown in Table 4. In each measurement, a sheet-like molded product made from the molded product of each of Prototype Examples 3-1 to 3-16 was used as a measurement sample.

[0125] [Preparation of measurement samples] Using a flat plate heating press (Imoto Machinery Co., Ltd., "IMC-19EB"), sheet-shaped measurement samples with a diameter of 80 mm and a thickness of 100 μm were prepared from each of the cellulose composite resin molded products of prototypes 3-1 to 3-16 under conditions of a flat plate temperature of 180°C and a pressure of 20 MPa.

[0126] [Measurement of the area ratio of coarse cellulose] Coarse cellulose is an aggregate of cellulose raw materials (cellulose fibers), and when the sheet-like measurement sample is observed using the digital microscope described below, the surface area measured on the observed image is less than 0.005 mm 2 The area ratio of coarse cellulose was determined as 100 mm 2The surface area ratio of coarse cellulose was defined as the ratio of the surface area of ​​the coarse cellulose to the area of ​​the cellulose. A small value for the coarse cellulose area ratio indicates that the defibration of the cellulose raw material is progressing. The coarse cellulose area ratio was measured automatically using a digital microscope (Keyence Corporation, "VHX-7000") to observe a sheet-like measurement sample at 20x magnification, and the automatic area measurement function was used.

[0127] [Measurement of aggregates in cellulose raw materials] The term "aggregates of cellulose raw material" refers to cellulose fibers that have been aggregated to form clumps. If the number of agglomerates of cellulose raw material contained in a cellulose composite resin molded product is large, it indicates that the cellulose raw material is not uniformly dispersed in the resin raw material. The number of agglomerates of cellulose raw material in a sheet-shaped measurement sample was counted visually. The agglomerates to be counted were those with a diameter of 0.5 mm or more. Cellulose raw material agglomerates with 10 or less were evaluated as "good", those with 11 to 20 were evaluated as "good", and those with 21 or more were evaluated as "bad".

[0128] [Measurement of tensile properties] Tensile strength and tensile modulus were measured as tensile properties. Tensile strength is an index for judging the strength of a cellulose composite resin molded product, and the tensile strength is increased, making the cellulose composite resin molded product less likely to break. Tensile modulus is an index for judging the rigidity of a cellulose composite resin molded product, and the tensile modulus is increased, making the cellulose composite resin molded product less likely to deform. In the measurement of tensile properties, a Thomson type was used to take a dumbbell-shaped measurement sample, which is a multipurpose test piece A12 type, from the sheet-like measurement sample described above, to prepare a measurement sample for tensile properties. Thereafter, the tensile strength (MPa) and tensile modulus (GPa) of the measurement sample were measured using a plastic tensile jig on a precision universal testing machine (manufactured by Shimadzu Corporation, "AGS-X"). The measurement conditions were a chuck distance of 60 mm and a test speed of 200 mm / min. The improvement rate of the measured values ​​of the tensile strength and tensile modulus of Prototype Examples 3-1 to 3-15 was calculated based on the measured value of Prototype Example 3-16 (blank) as the reference (100%). Tensile strength of 100% or more was evaluated as "good", and less than 100% was evaluated as "poor". Tensile modulus of elasticity of 100% or more was evaluated as "good", and less than 100% was evaluated as "poor".

[0129] In addition, for the overall evaluation, if there was even one "X" in each evaluation, it was rated as unsuccessful with an "X", if there was no "X" and at least one "△", it was rated as acceptable with a "△", and all other evaluations were rated as good with an "O".

[0130] [Table 4]

[0131] [Results and Discussion] In the shearing process, the cellulose-containing master batch (Prototype Examples 2-1 (B1) to 2-9 (B9), 2-13 (B13)) prepared using the cellulose-containing resin additive (Prototype Examples 1-1 (A1) to 1-9 (A9), 1-13 (A13)) solid-phase sheared using a polyolefin having a weight average molecular weight of 40,000 or less was added to the prototypes 3-1 to 3-9 and 3-13, which have excellent tensile properties compared to the blank prototype 3-16, as shown in Table 4. There were no agglomerates of the cellulose raw material, and the (defibrated) cellulose was well dispersed. It is considered that the cellulose-containing master batch resin moldings of the prototypes 2-1 (B1) to 2-9 (B9) and 2-13 (B13) showed excellent effects as a reinforcing material.

[0132] In addition, in prototype 3-10, which was added with a cellulose-containing masterbatch (prototype 2-10 (B10)) prepared using a cellulose-containing resin additive (prototype 1-10 (A10)) that was solid-phase sheared using a polyolefin with a weight-average molecular weight of 153,000, there were more agglomerates of the cellulose raw material and the dispersibility of the cellulose was inferior to that of the prototype using a cellulose-containing masterbatch prepared using a cellulose-containing resin additive that was solid-phase sheared using a polyolefin with a smaller weight-average molecular weight. However, the tensile properties were superior to those of prototype 3-16, and it is believed that the cellulose-containing masterbatch resin molding of prototype 2-10 (B10) demonstrated a sufficiently excellent effect as a reinforcing material.

[0133] Comparing Prototype 3-6 and Prototype 3-14, which have the same blend of cellulose raw materials and resin raw materials, the two differ in that Prototype 3-6 uses a cellulose-containing master batch (Prototype 2-6 (B6)) obtained from a cellulose-containing resin additive (Prototype 1-6 (A6)) that has been subjected to solid-phase shearing, while Prototype 3-14 uses a cellulose-containing master batch (Prototype 2-14 (B14)) obtained without performing solid-phase shearing of the raw material. Therefore, when comparing the coarse cellulose area ratios of Prototype 3-6 and Prototype 3-14, Prototype 3-6 had a large value of 39 compared to 51 for Prototype 3-14. Note that the aggregates are aggregates formed by the aggregation of defibrated cellulose by hydrogen bonding, so no aggregates are generated in Prototype 3-14, which has not been subjected to solid-phase shearing.

[0134] From this, it can be said that in prototype 3-14, which was molded from raw materials that were not subjected to solid-state shearing, the cellulose raw materials were not sufficiently defibrated and a large amount of undefibrated cellulose was contained. In contrast, it is believed that in prototype 3-6, the cellulose raw materials were properly defibrated by performing solid-state shearing. Therefore, in prototype 3-6, in which defibrated cellulose was uniformly dispersed in the resin raw materials, the reinforcing effect of cellulose was effectively exerted, improving the tensile properties, while in prototype 3-14, in which undefibrated cellulose remained, the tensile strength was reduced. Therefore, it is believed that producing a cellulose-containing resin additive by performing solid-state shearing is effective in promoting the defibration of the cellulose raw materials and improving the tensile properties.

[0135] Next, among the cellulose composite resin molded products obtained by solid-phase shearing, the good prototypes 3-1 and 3-6 are compared with the prototype 3-12, which has deteriorated tensile strength. The difference is that the resin raw material M1 during the manufacture of the cellulose-containing resin additive in the prototype 3-1 has a weight-average molecular weight of 3800, the resin raw material M3 in the prototype 3-6 has a weight-average molecular weight of 15000, and the resin raw material M8 in the prototype 3-12 has a weight-average molecular weight of 510000. Comparing the aggregates of the prototypes 3-1 and 3-6 with those of the prototype 3-12, the aggregates of the prototypes 3-1 and 3-6 are 0, while the aggregates of the prototype 3-12 are 84. In other words, in the prototype 3-12, the cellulose raw material defibrated by solid-phase shearing aggregates and the tensile strength decreases, while in the prototypes 3-1 and 3-6, the cellulose raw material defibrated by solid-phase shearing is uniformly dispersed in the resin raw material, so that the tensile properties are improved.

[0136] From this, it is considered that the weight average molecular weight of the resin raw material affects the dispersibility of the cellulose raw material during solid-phase shearing, and that when low molecular weight polyolefin resins such as resin raw materials M1 and M3 are used, the cellulose raw material is more likely to be uniformly dispersed in the resin raw material, while when high molecular weight resins such as resin raw material M8 are used, agglomerates are more likely to occur. The resins with weight average molecular weights of about 3800 and 15000 used in prototypes 3-1 and 3-6 are very small as weight average molecular weights of resin raw materials, and are considered to be made into particulate resin materials by solid-phase shearing and to be able to penetrate, for example, between the fibers of the cellulose raw material. Therefore, it is considered that such low molecular weight resin raw materials (particulate resin materials) penetrate between the fibers of the cellulose raw material and the cellulose raw material is uniformly dispersed in the resin raw material.

[0137] Here, when Prototype Example 3-8 using resin raw material M4, which has a weight average molecular weight larger than resin raw material M1 and M3 of Prototype Examples 3-1 and 3-6 and a weight average molecular weight smaller than resin raw material M8 of Prototype Example 3-12, and Prototype Example 3-9 using resin raw material M5 were examined, no aggregates were observed as in Prototype Examples 3-1 and 3-6, and good tensile properties were obtained. The weight average molecular weight of resin raw material M4 is about 30,000, and the weight average molecular weight of resin raw material M5 is about 40,000, and it is considered that resin raw materials M4 and M5 can penetrate between the fibers of the cellulose raw material like resin raw material M3. Therefore, it is considered that polyolefins with small weight average molecular weights are preferable as resin raw materials to be mixed with the cellulose raw material during solid-phase shearing.

[0138] Then, the prototypes 3-10 to 3-12 are compared. The prototypes 3-10 to 3-12 using resin raw materials M6 to M8 with weight average molecular weights of 153,000, 250,000, and 510,000 are superior in tensile properties compared to the prototype 3-16, which is blank, with only the prototype 10. In the prototypes 3-11 and 3-12, which use a cellulose-containing masterbatch (Prototype 2-11 (B11), Prototype 2-12 (B12)) obtained from a cellulose-containing resin additive (Prototype 1-11 (A11), Prototype 1-12 (A12)) with a large weight average molecular weight of the thermoplastic resin used in the shearing process, the (fibrillated) cellulose is not uniformly dispersed in the resin raw material, and the number of aggregates increases, which is considered to have reduced tensile strength. Therefore, in view of these measurement or evaluation results, it is understood that the weight average molecular weight of the thermoplastic resin used in the shearing process should be 160,000 or less.

[0139] The cellulose composite resin molded products of Prototype Examples 3-7 and 3-8 are different from the cellulose composite resin molded product of Prototype Example 3-6 in that Prototype Example 3-6 used resin raw material M3 in the production of the cellulose-containing resin additive, whereas Prototype Example 3-8 used acid-modified polyolefin resin raw material M4 in the production of the cellulose-containing resin additive. Also, the cellulose composite resin molded product of Prototype Example 3-7 is different from the cellulose composite resin molded product of Prototype Example 3-6 in that Prototype Example 3-6 used only resin raw material M3 in the production of the cellulose-containing resin additive, whereas Prototype Example 3-7 used both M3 and acid-modified polyolefin resin raw material M4 in the production of the cellulose-containing resin additive.

[0140] In Prototypes 3-7 and 3-8, the improvement rate of the measured tensile strength relative to the measured value of Prototype 3-16 (blank) is greater than that of Prototype 3-6, which does not use acid-modified polyolefin. Since acid-modified polyolefin has a hydrophilic group, it is considered that it has good affinity with the cellulose raw material. Therefore, when acid-modified polyolefin is used in the production of cellulose-containing resin additives, as in Prototypes 3-7 and 3-8, the cellulose raw material as a reinforcing material is firmly bonded to the resin raw material, which is considered to have contributed to the improvement of tensile strength.

[0141] In addition, when the tensile modulus of Prototype Examples 3-6 to 3-8 is examined, it is found that the improvement rate of the measured value of the tensile modulus of Prototype Examples 3-6 and 3-7 relative to the measured value of Prototype Example 3-16 (blank) is greater than that of Prototype Example 3-8. In Prototype Example 3-8, in the cellulose-containing resin additive used as the molding raw material, resin raw material M4 having a weight average molecular weight of the resin raw material greater than that of Prototype Examples 3-6 and 3-7 is used. Similarly, when Prototype Example 3-6 and Prototype Example 3-7 are compared, Prototype Example 3-6, which does not contain resin raw material M4 having a large weight average molecular weight, had a higher improvement rate of the tensile modulus of Prototype Example 3-7, which contains resin raw material M4. In other words, it was shown that the lower the molecular weight of the resin raw material of the cellulose-containing resin additive, the more the tensile modulus of the molded product is improved.

[0142] For this reason, it is preferable to use a resin raw material with a smaller weight average molecular weight in a cellulose-containing resin additive. This is thought to be because the low molecular weight resin material becomes a resin material broken down into fine particles by solid-phase shearing, making it easier to penetrate between the fibers of the defibrated cellulose, and integrating with the defibrated cellulose is promoted. Therefore, the cellulose raw material (defibrated cellulose) as a reinforcing material is uniformly dispersed in the fine particle-shaped resin raw material, which is thought to contribute to improving the tensile modulus.

[0143] The cellulose composite resin molded products of prototypes 3-2 to 3-5, 3-7, and 3-13, which use multiple thermoplastic resins that are polyolefins used in the shearing process, are compared. Prototypes 3-2 to 3-5 and 3-7, which use resin raw materials M2 to M4 with weight-average molecular weights of 10,000, 15,000, and 30,000, all have superior tensile properties compared to the blank prototype 3-16. There are no agglomerates of the cellulose raw material, and (defibrated) cellulose is well dispersed. It is believed that the cellulose-containing master batch resin molded products of prototypes 2-2 (B2) to 2-5 (B5) and 2-7 (B7) exhibit excellent effects as reinforcing materials.

[0144] In other words, it was shown that a plurality of thermoplastic resins, which are polyolefins having small weight average molecular weights, may be used in the shearing process. It was also shown that the thermoplastic resin can be satisfactorily defibrated even when the amount added to the cellulose raw material is small.

[0145] Furthermore, when considering prototype example 3-13, resin raw material M2 with a weight-average molecular weight of 10,000 and resin raw material M7 with a weight-average molecular weight of 250,000 were added in the shearing process, and it is believed that the cellulose raw material (defibrated cellulose) as a reinforcing material was uniformly dispersed in the finely divided resin raw material, contributing to the improvement of the tensile modulus. For this reason, it is acceptable for multiple thermoplastic resins to be used in the shearing process, and it is believed that the desired dispersibility of the cellulose raw material (defibrated cellulose) can be obtained as long as the thermoplastic resins added include one with a small weight-average molecular weight.

[0146] Furthermore, in the case of prototype 3-15, in which a cellulose-containing resin additive (prototype 1-2) that was solid-phase sheared using a polyolefin having a weight-average molecular weight of 15,000 was added, there were more aggregates of the cellulose raw material and the dispersibility of cellulose was inferior compared to prototype 3-2, in which a cellulose-containing masterbatch (prototype 2-2) prepared using the same cellulose-containing resin additive (prototype 1-2) was added, but the tensile properties were superior to those of prototype 3-16. It is considered that the dispersion of (fibrillated) cellulose was inferior to that in the case of a cellulose-containing masterbatch because the cellulose-containing resin additive was not heated and kneaded to form a cellulose-containing masterbatch. However, even when the cellulose-containing resin additive was directly added, the tensile properties of the cellulose composite resin molded product were improved, so it is considered that a sufficiently excellent effect as a reinforcing material can be exhibited. Therefore, it is understood that the cellulose composite resin molded product obtained by adding the cellulose-containing resin additive to the polyolefin resin raw material also has excellent tensile properties.

[0147] As shown in Table 3, it is also beneficial that the blending ratio of the cellulose raw material C1 to the cellulose composite resin molded products of Prototype Examples 3-1 to 3-10, 3-13, and 3-15 may be as low as 10 parts by mass. In other words, even if the blending ratio of the cellulose raw material C1 as a reinforcing material to the cellulose composite resin molded product is low, a cellulose composite resin molded product having excellent tensile properties can be produced.

[0148] From the above considerations, when the relationship between the thermoplastic resin raw material used in the production of the cellulose-containing resin additive (shearing process) and the aggregates of the cellulose raw material contained in the cellulose composite resin molding was examined, it was confirmed that there were no aggregates or only a very small amount of them when the weight average molecular weight of the resin raw material was a low molecular weight that could penetrate between the fibers of the cellulose raw material, that is, 160000 or less, as in prototypes 3-1 to 3-10, 3-13, and 3-15. Furthermore, when the relationship between the thermoplastic resin raw material of the cellulose-containing resin additive and the tensile properties (tensile strength, tensile modulus) was examined, it was confirmed that when the weight average molecular weight of the resin raw material was a low molecular weight of 160000 or less, it contributed to improving both the tensile strength and the tensile modulus.

[0149] For this reason, it is considered that making the weight-average molecular weight of the thermoplastic resin raw material used in the cellulose-containing resin additive 160,000 or less is effective as an indicator showing the progress of defibration of the cellulose raw material and an indicator of improving the tensile properties of the cellulose composite resin molded product. Therefore, considering the measurement or evaluation results of the agglomerates and tensile properties, it is considered that the thermoplastic resin raw material of the cellulose-containing resin additive needs to be a low-molecular-weight polyolefin with a weight-average molecular weight of 160,000 or less.

[0150] As described above, the manufacturing method (H1) of the cellulose-containing resin additive of the present invention is a manufacturing method of a cellulose-containing resin additive used in the manufacture of a cellulose composite resin molded product, and includes a cellulose swelling process (S1) in which a solvent is added to an undefibrated cellulose raw material to obtain a cellulose swollen material in which the cellulose raw material is swelled, and a shearing process (S2) in which a thermoplastic resin raw material that is a low-molecular-weight polyolefin having a weight-average molecular weight of 160,000 or less and the cellulose swellable material are mixed and solid-phase sheared at a temperature range below the boiling point of the solvent and at which the thermoplastic resin raw material does not melt, and in the shearing process (S2), the thermoplastic resin raw material is broken down into a particulate resin material, and the cellulose swellable material is defibrated into defibrated cellulose, and the particulate resin material further penetrates between the fibers of the defibrated cellulose to obtain a cellulose-containing resin additive, so that a cellulose-containing resin additive used for obtaining a cellulose composite resin molded product in which the cellulose raw material is uniformly dispersed in the thermoplastic resin raw material can be simply and efficiently manufactured.

[0151] In addition, the cellulose-containing masterbatch manufacturing method (H2) of the present invention has a cellulose-containing masterbatch molding step (S3) in which the cellulose-containing resin additive obtained by the cellulose-containing resin additive manufacturing method (H1) of the present invention is heated, kneaded, and molded to obtain a cellulose-containing masterbatch, so that a cellulose-containing masterbatch in which a cellulose raw material is uniformly dispersed in a thermoplastic resin raw material can be easily and efficiently manufactured. In addition, by performing the cellulose-containing masterbatch molding step (S3) continuously after the manufacture of the cellulose-containing resin additive, even if the cellulose-containing resin additive is in a powder form and handling such as storage is somewhat complicated, the molding step can be performed regardless of the handling of the cellulose-containing resin additive, and a cellulose-containing masterbatch can be efficiently manufactured from the cellulose-containing resin additive. Furthermore, the cellulose-containing masterbatch manufactured can be molded (pelletized) by removing moisture by heating and kneading, which improves ease of handling when storing, etc.

[0152] Furthermore, the method for producing a cellulose composite resin molded product (H3) of the present invention has a cellulose composite resin molding step (S4) in which the cellulose-containing masterbatch obtained by the method for producing a cellulose-containing masterbatch (H2) of the present invention is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product, so that a cellulose composite resin molded product in which the cellulose raw material is uniformly dispersed in a thermoplastic resin raw material can be produced simply and efficiently. In addition, since the cellulose-containing masterbatch is in a form suitable for storage, transportation, etc., a cellulose composite resin molded product can be easily produced even if the cellulose composite resin molding step (S4) is performed using a cellulose-containing masterbatch separately produced by the method for producing a cellulose-containing masterbatch (H2). Therefore, it can be particularly preferably carried out in cases where the step of producing the cellulose-containing masterbatch and the step of molding the cellulose composite resin molded product (S4) are performed in different facilities, etc.

[0153] In addition, the method for producing a cellulose composite resin molded product (H4) of the present invention has a cellulose composite resin molding step (S5) in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive (H1) of the present invention is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product, so that a cellulose composite resin molded product in which a cellulose raw material is uniformly dispersed in a thermoplastic resin raw material can be produced simply and efficiently. In addition, since the cellulose composite resin molding step (S5) is performed continuously from the method for producing a cellulose-containing resin additive (H1), a cellulose composite resin molded product can be directly produced from the step of producing a cellulose-containing resin additive without using a cellulose-containing master batch, and a cellulose composite resin molded product can be produced more efficiently. Therefore, the method for producing a cellulose composite resin molded product (H4) is suitable for cases where the step of producing a cellulose composite resin molded product from cellulose and resin raw materials is continuously carried out in the same facility, etc. [Industrial Applicability]

[0154] As described above, according to the method for producing a cellulose-containing resin additive (H1) of the present invention, a cellulose-containing resin additive used for obtaining a cellulose composite resin molded product in which a cellulose raw material is uniformly dispersed in a resin raw material can be produced simply and efficiently. Furthermore, according to the method for producing a cellulose-containing masterbatch (H2) of the present invention, a cellulose-containing masterbatch in which a cellulose raw material is uniformly dispersed in a thermoplastic resin raw material can be produced simply and efficiently using the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive of the present invention. In addition, according to the method for producing a cellulose composite resin molded product (H3) of the present invention, a cellulose composite resin molded product in which a cellulose raw material is uniformly dispersed in a thermoplastic resin raw material can be produced simply and efficiently using the cellulose-containing masterbatch obtained by the method for producing a cellulose-containing masterbatch (H2) of the present invention. Furthermore, according to the method for producing a cellulose composite resin molded product (H4) of the present invention, a cellulose composite resin molded product in which a cellulose raw material is uniformly dispersed in a thermoplastic resin raw material can be produced simply and efficiently using the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive (H1) of the present invention. For this reason, the present invention is suitable as a method for producing reinforcing materials and substrates for cellulose composite resin molded products such as building parts and automobile interior parts, and is promising as a method for producing new alternatives to such reinforcing materials, substrates, and cellulose composite resin molded products.

Claims

1. A method for producing a cellulose-containing resin additive used in the production of a cellulose composite resin molded product, comprising: a cellulose swelling step in which a solvent is added to an undefibrated cellulose raw material to obtain a cellulose swollen material by swelling the cellulose raw material; a shearing step in which a thermoplastic resin raw material, which is a polyolefin having a weight average molecular weight of 160,000 or less, and the cellulose swelling material are mixed and subjected to solid-phase shearing at a temperature range that is lower than the boiling point of the solvent and does not melt the thermoplastic resin raw material; In the shearing process, the thermoplastic resin raw material is broken down into a particulate resin material, and the cellulose swelling material is defibrated into defibrated cellulose, and the particulate resin material further penetrates between the fibers of the defibrated cellulose to obtain a cellulose-containing resin additive. A method for producing a cellulose-containing resin additive comprising the steps of:

2. The method for producing a cellulose-containing resin additive according to claim 1, wherein the thermoplastic resin raw material comprises an acid-modified polyolefin.

3. The method for producing a cellulose-containing resin additive according to claim 1 or 2, wherein the solvent is water.

4. The method for producing a cellulose-containing resin additive according to claim 1 or 2, wherein the average fiber diameter of the cellulose raw material is 10 to 40 μm.

5. The method for producing a cellulose-containing resin additive according to claim 3, wherein the average fiber diameter of the cellulose raw material is 10 to 40 μm.

6. A method for producing a cellulose-containing masterbatch, comprising a cellulose-containing masterbatch molding step in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive according to claim 1 or 2 is heated, kneaded, and molded to obtain a cellulose-containing masterbatch.

7. A method for producing a cellulose-containing masterbatch, comprising a cellulose-containing masterbatch molding step in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive according to claim 3 is heated, kneaded, and molded to obtain a cellulose-containing masterbatch.

8. A method for producing a cellulose-containing masterbatch, comprising a cellulose-containing masterbatch molding step in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive according to claim 4 is heated, kneaded, and molded to obtain a cellulose-containing masterbatch.

9. A method for producing a cellulose-containing masterbatch, comprising a cellulose-containing masterbatch molding step in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive according to claim 5 is heated, kneaded, and molded to obtain a cellulose-containing masterbatch.

10. A method for producing a cellulose composite resin molded product, comprising a cellulose composite resin molding step (S4) in which the cellulose-containing masterbatch obtained by the method for producing a cellulose-containing masterbatch according to claim 6 is added to a polyolefin resin raw material, and the cellulose-containing masterbatch is heated, kneaded, and molded to obtain a cellulose composite resin molded product.

11. A method for producing a cellulose composite resin molded product, comprising a cellulose composite resin molding step (S4) in which the cellulose-containing masterbatch obtained by the method for producing a cellulose-containing masterbatch according to claim 7 is added to a polyolefin resin raw material, and the cellulose-containing masterbatch is heated, kneaded, and molded to obtain a cellulose composite resin molded product.

12. A method for producing a cellulose composite resin molded product, comprising a cellulose composite resin molding step (S4) in which the cellulose-containing masterbatch obtained by the method for producing a cellulose-containing masterbatch according to claim 8 is added to a polyolefin resin raw material, and the cellulose-containing masterbatch is heated, kneaded, and molded to obtain a cellulose composite resin molded product.

13. A method for producing a cellulose composite resin molded product, comprising a cellulose composite resin molding step (S4) in which the cellulose-containing masterbatch obtained by the method for producing a cellulose-containing masterbatch according to claim 9 is added to a polyolefin resin raw material, and the cellulose-containing masterbatch is heated, kneaded, and molded to obtain a cellulose composite resin molded product.

14. A method for producing a cellulose composite resin molded product, comprising a cellulose composite resin molding step (S5) in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive according to claim 1 or 2 is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product.

15. A method for producing a cellulose composite resin molded product, comprising a cellulose composite resin molding step (S5) in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive according to claim 3 is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product.

16. A method for producing a cellulose composite resin molded product, comprising a cellulose composite resin molding step (S5) in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive according to claim 4 is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product.

17. A method for producing a cellulose composite resin molded product, comprising a cellulose composite resin molding step (S5) in which the cellulose-containing resin additive obtained by the method for producing a cellulose-containing resin additive according to claim 5 is added to a polyolefin resin raw material, heated and kneaded, and molded to obtain a cellulose composite resin molded product.

Images