JP2018177965A - Manufacturing method of composite material containing cellulose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome situation that a treatment method capable of continuous production at low cost without using a specific device, although various methods for using a nanofiber by micronizing a cellulose fiber to nano-order as a filler and blending the same into a resin are proposed for improving physical properties such as resin strength.SOLUTION: A manufacturing method of a composite material containing cellulose has a process for adding an addition material to a material containing cellulose, and chemically modifying and/or fibrillating them, a process for separating and removing at least a part of the additive material as excess from cellulose of which a part is chemically modified and/or fibrillated by the addition material, and a process for mixing cellulose chemically modified and/or fibrillated by the addition material and a thermoplastic resin. Because the above described can be achieved by using a two-shaft type extruder which is generally used thereby, the composite material can be produced at low cost and in short time.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a resin molded product in which a resin and a cellulose nanofiber after disintegration of a cellulose fiber are combined.

  Conventionally, it is known to use a filler to improve the physical strength of the resin. For example, a molding material obtained by microfibrillating cellulose fibers and using microfibrillated plant fibers (nanofibers) or the like whose fiber diameter has been reduced to nano order as a filler and incorporating nanofibers in a resin Has attracted attention as a useful material because it is lighter in weight and higher in strength than metals and the like.

  Various methods are known for producing cellulose nanofibers from fibers such as plants. Generally, cellulose fiber-containing materials such as pulp are disintegrated and refined by grinding and refining by refiner, grinder (stone mill type grinder), twin-screw kneader (double-screw extruder), high-pressure homogenizer, etc. Manufactured.

  When an aggregate of cellulose nanofibers obtained by these methods is formed into a sheet, or when cellulose nanofibers and a resin are mixed to form a resin composite, generally, the fiber length and diameter of the cellulose nanofibers It is known that when the ratio (aspect ratio) is larger, the strength of the sheet or the resin composite is higher, and a modification method for improving the affinity to a resin is widely studied. There is.

JP 2007-231438 A JP 2008-75214 A JP 2007-51266 A Unexamined-Japanese-Patent No. 11-513425 gazette JP, 2009-293167, A

  The most common method of disintegrating pulp is to disintegrate in the presence of water. After fibrillation, the drainage time when separating water and the obtained cellulose nanofibers becomes longer as the aspect ratio of the cellulose nanofibers becomes larger. That is, when it is intended to obtain a sheet or resin complex of high strength cellulose nanofibers, it is desirable to break up into cellulose nanofibers with a high aspect ratio, but when the fiber diameter is small and the aspect ratio is large, drainage The time will be long, and it will be an industrial cost increase factor.

  For example, in Patent Document 1, absorbent cotton is fibrillated by a high pressure homogenizer to obtain microfibrillar cellulose. However, when raw fibers such as pulp are disintegrated by a high-pressure homogenizer, the diameter of the fibers is generally reduced and the aspect ratio is increased, so that high sheet strength can be exhibited, but drainage when forming a cellulose nanofiber sheet It is not preferable industrially because the time is extremely long.

Further, in Patent Document 2, pulp pre-fibrillated with a refiner is disintegrated using a twin-screw extruder under conditions of a screw rotation speed of 300 rpm (a screw diameter is 15 mm, and a peripheral speed is 14.1 m / min). , Has become fine fiber. However, as described above, under such conditions, the microfibrillation (fiber nanoization) is insufficient because the pulp does not apply a high shear rate and the cutting preferentially proceeds over fiber disintegration. It is difficult to obtain nanofibers with high sheet strength.

  Since microfibrillated plant fibers are very cohesive and generally incompatible with resins, it is difficult to obtain a uniform resin molding material in which the microfibrillated fibers are uniformly dispersed. Therefore, the resulting molding material has a problem that mechanical strength can not be sufficiently exhibited. In order to solve such problems, attempts have been made to modify the surface of microfibrillated plant fibers with a chemical modifier or the like to improve the dispersibility in the resin.

  For example, Patent Document 1 discloses a composite material obtained by impregnating a matrix material with an aggregate of chemically modified cellulose fibers. It is an object of the present invention to obtain a high quality transparent substrate by a method (sheet impregnation method) in which a cellulose fiber modified by such a chemical modifier and a matrix material are complexed. However, in Patent Document 3, since the sheet impregnation method is used, the resin needs to be in a liquid state, and it is difficult to use for complexation with an olefin resin which is usually solid. Further, it is easy to form a dense sheet as the degree of defibrillation of the cellulose fiber is increased, and it is difficult to impregnate the resin uniformly to the inside, so that the resin concentration tends to vary in the sheet inside and on the surface. For this reason, there existed a problem that mechanical strength was not fully obtained.

  Patent Document 4 discloses cellulose microfibrils whose surface hydroxyl group is esterified with an organic compound such as acetic anhydride, butyric anhydride, acetyl chloride, butyryl chloride, acetic acid and the like. Patent Document 4 describes that the cellulose microfibrils are dissolved in an organic solvent, mixed with a resin dissolved in the organic solvent, and then the solvent is removed to form a composite material. When a composite material is obtained by such a method, it is necessary to sufficiently dissolve cellulose microfibrils in an organic solvent. In order to dissolve cellulose fibers in an organic solvent, it is necessary to sufficiently carry out hydrophobic modification of cellulose microfibrils. Such hydrophobic modification results in the destruction of cellulose fiber crystals, making it difficult to produce high strength composite materials.

  Further, in Patent Document 5, after a part of hydroxyl groups of cellulose is esterified with polybasic acid anhydride such as maleic anhydride or succinic anhydride and a carboxyl group is introduced, high pressure homogenizer treatment, kneader, multi-screw extruder, etc. A method of obtaining nanofibers by microfibrillation treatment according to the present invention and a composite material comprising the nanofibers and a resin are disclosed. The nanofibers induce repulsion between microfibrils by the presence of the negatively charged carboxyl group introduced to the surface of the microfibrils, enabling stable dispersion in the dispersion. However, in the present document, it is considered that it is difficult to apply to mass production since processing in a plurality of different devices such as a steaming / concentration processing step, a solvent extraction step, a swelling step is required until the final stage.

  The inventors of the present invention have been proposed in view of such a situation, and while maintaining the aspect ratio of the nanocellulose fiber appropriately, the industrial process does not require a large amount of time for the pretreatment process and the post-treatment process. It is an object of the present invention to provide a new manufacturing method that is also useful.

  In the method of producing a composite material containing cellulose of the present disclosure, an additive is added to a material containing cellulose, and chemical modification and / or disintegration is performed, and at least a part of the cellulose is chemically modified by the additive. The method further comprises the steps of separating and removing at least a part of the additive material which has become surplus from the disintegrated cellulose, and kneading the cellulose chemically modified and / or disintegrated by the additive material and a resin.

  In the method for producing a cellulose composite material according to the present invention, removal of additives and various solvents used in chemical modification and composite kneading with a resin, which were essential in the conventional method, can be performed in one step. As a result, continuous processing can be performed, and additives used can be recycled and reused, so that it is possible to provide a processing method in a short time process at low cost.

The figure which shows an example of the apparatus which manufactures the cellulose composite material in Embodiment 1. Sectional view of screw and cylinder in Embodiment 1 Sectional drawing of screw and cylinder seen from different directions in Embodiment 1 Sectional view of screw, cylinder and seal ring in Embodiment 1 Cross section of screw, cylinder and seal ring seen from different directions in Embodiment 1

  Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, the detailed description may be omitted if necessary. For example, detailed description of already well-known matters and redundant description of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art.

  It should be noted that the attached drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and they are not intended to limit the claimed subject matter.

Embodiment 1
FIG. 1 is a diagram showing an example of an apparatus for producing a composite material containing cellulose according to Embodiment 1, and the operation will also be described.

  In FIG. 1, the twin-screw kneading apparatus 1 has the minimum basic configuration in the present embodiment. The twin-screw kneader 1 has one motor 2 as a single drive mechanism, a twin screw 3 driven by the motor 2, a cylinder 4 penetrated by the screw 3, and a heater covering the cylinder 4 ing. The twin screw 3 kneads the thermoplastic resin and the cellulose chemically modified and / or disintegrated by the additive. A heater covering around the cylinder 4 maintains a heating environment such as chemical modification and / or defibration, and kneading of resin.

  The twin-screw kneader 1 includes an inlet 5 for feeding cellulose as a raw material and an additive, an outlet 6 for separating and removing at least a part of the surplus additive, and at least a part of the additive. It has an inlet 7 for introducing a resin into the chemically modified and / or disintegrated cellulose after removal, and an outlet 8 for discharging a composite material of cellulose and resin at the farthest side from the motor 2.

  FIG. 2 shows a cross-sectional view of the screw 3 and the cylinder 4 viewed from the insertion direction of the cellulose etc. of the inlet 5. FIG. 3 shows a cross-sectional view of the screw 3 and the cylinder 4 viewed from the axial direction of the screw 3. Cellulose in a solid or liquid state, additives and resin enter the gap between the screw 3 and the cylinder 4 and the gap between the screw 3 and move as the biaxial screw 3 rotates. As shown in FIG. 3, the screw 3 has an elliptical cross section, and is disposed to be orthogonal to each other in the major axis direction of the ellipse. In addition, although the case where the cross section of the screw 3 is an elliptical shape is demonstrated in this Embodiment, the shape of the screw 3 is not limited to this, Another shape may be sufficient.

  In the present embodiment, the step of chemically modifying and / or disaggregating is performed in zone 9, the step of separating and removing at least a part of the surplus additive is performed in zone 10, and the chemical modification and / or The step of kneading the defibrated cellulose and the thermoplastic resin corresponds to the zone 11.

  Cellulose used in the present embodiment may be any as long as it can be easily and inexpensively obtained from trees, wood, pulp and the like, and agricultural waste and food processing by-products and the like can be used besides them.

  Moreover, as an additive to be used to chemically modify and / or disintegrate cellulose used in the present embodiment, mention may be made of an esterification agent for chemically modifying and a plasticizer for promoting fibrillation. Can.

  Examples of the esterification agent for chemical modification include dibasic acid anhydride and the like. Specifically, maleic anhydride, succinic anhydride, phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, anhydride Dichloromaleic acid, itaconic anhydride, tetrabromophthalic anhydride, pyromellitic anhydride and the like can be mentioned.

  Since the melting point of these dibasic acid anhydrides is usually higher than normal temperature, these dibasic acid anhydrides are in a powder state at normal temperature, and are introduced from the input port 5 together with cellulose using a feeder or the like. The zone 9 heats the cylinder 4 with a heater and is maintained at a temperature which is equal to or higher than the melting point of the dibasic acid anhydride. As a result, these dibasic acid anhydrides are heated and kneaded with the added cellulose, and an esterification reaction occurs from the surface of the cellulose, and the esterification of the hydroxyl groups of the cellulose proceeds according to the reaction conditions, and aggregation by hydrogen bonds It is possible to alleviate the situation. As a result, it is possible to suppress reaggregation, that is, to promote defibration, and cellulose is more easily mixed at the time of subsequent kneading with the resin. Thereafter, in the zone 10, the excess dibasic acid anhydride is separated from the cellulose by utilizing the pressure difference in the cylinder 4, and is discharged and recovered in a liquid state from the discharge port 6.

  Moreover, as a plasticizer for promoting disintegration, there is a linear or cyclic aliphatic hydrocarbon. Specifically, liquid paraffin, nonane, decane, decalin, paraxylene, undecane, dodecane, mineral oil fractions whose boiling points correspond to these, and the like can be mentioned.

  Since the plasticizer is usually in a liquid state at room temperature, an apparatus for injecting a liquid such as a gear pump may be separately used when charging the plasticizer with the cellulose. The plasticizer is introduced together with the cellulose from the inlet 5 and heat-kneaded in the zone 9 so that the plasticizer gradually penetrates from the surface of the cellulose, and the plasticization of the cellulose, that is, the defibrillation can be promoted. As a result, the cellulose is more easily mixed at the time of the subsequent kneading with the resin. Thereafter, in the zone 10, the surplus plasticizer is separated from the cellulose by utilizing the pressure difference in the cylinder 4, and is discharged and recovered in the liquid state from the discharge port 6.

  The above-mentioned esterifying agent for chemical modification and the plasticizer for promoting disintegration may be mixed together and kneaded with cellulose. By utilizing both additives, since relaxation of the aggregation state by esterification and defibrillation by the addition of the plasticizer simultaneously proceed, the kneading with the resin becomes better.

  In this case, the temperature in the cylinder 4 in the zone 9 is preferably 30 to 150 ° C., and the temperature in the cylinder 4 in the zone 10 is preferably about 120 to 170 ° C.

The resin to be introduced at the inlet 7 is not particularly limited as long as it can be kneaded with cellulose, and polypropylene, polystyrene, poly (acrylonitrile-butadiene-styrene copolymer), polyamide, etc. It does not matter with something like

  The discharge mechanism of the additive from the discharge port 6 will be described in detail. In the zone 11 from the inlet 7 to the outlet 8 where the cellulose composite material is discharged, in the gap between the cylinder 4 and the screw 3 in order to knead the chemically modified and / or disintegrated cellulose and the resin. Is filled with the resin, and the resin pressure is high toward the discharge port 8. Therefore, the additive in the liquid state, which has moved from zone 9 to zone 10, is lower than the resin pressure in the cylinder 4, and therefore, is discharged at the discharge port 6. At this time, in order to improve the separation efficiency of the surplus additive material, it is also effective to provide a weir like a seal ring, for example. FIG. 4 shows a cross-sectional view of the screw 3, the cylinder 4 and the seal ring 12 as viewed from the insertion direction of the cellulose etc. of the inlet 5. FIG. 5 shows a cross-sectional view of the screw 3, the cylinder 4 and the seal ring 12 viewed from the axial direction of the screw 3. As described above, the surplus additive material in the liquid state can be easily recovered and discharged from the discharge port 6 by the inlet 7 and the pressurizing mechanism by the seal ring. Further, since an additive having a certain concentration may be present even in the zone 11, although not shown in FIG. 1, a vent port or the like may be provided in the vicinity of the exhaust port 8 to promote separation from resin. It is.

  Excess additive material is removed, and the chemically modified and / or defibrated cellulose by the additive is kneaded in zone 11 with the thermoplastic resin introduced from the inlet 7 and finally from the outlet 8 of the cellulose composite material , Will be discharged.

  The temperature in the cylinder 4 in the zone 11 at this time is preferably 160 to 200 ° C.

  As described above, by using the manufacturing method according to the present embodiment, it has an independent drive mechanism without passing through another reaction process, separation, concentration step, etc. in another device in the middle of the process of the cellulose once charged. Since it becomes possible to treat all through the apparatus, it is possible to produce a composite material containing cellulose in a very efficient and mass-producible manner.

  Each embodiment will be described below. However, the present invention is not limited at all by these examples and the like. The physical properties of the composite material containing cellulose obtained in the present example were evaluated by the following test methods.

  The tensile strength test and the bending elasticity test are made in accordance with the ISO test method, and the test pieces of the ISO standard are made, and the tensile test (JIS-K-7161) and the bending test (JIS-K-7117), the Charpy impact test (JIS) -K-7111) was performed.

Example 1
Example 1 using the twin-screw kneading apparatus 1 of FIG. 1 will be described. As a PP resin, BC03B (manufactured by Nippon Polypropylene Corporation) is introduced from the inlet 7. The temperature of the zone 11 is set to 150 to 200 ° C. from the inlet 7 to the outlet 8 and the resin is kneaded. After it is confirmed that the resin is discharged from the discharge port 8 and the resin pressure of the cylinder 4 in the zone 11 is sufficiently boosted, the cellulose and the additive are introduced into the inlet 5. As cellulose powder, Theorus FD-101 (manufactured by Asahi Kasei Chemicals Corporation) is used. Maleic anhydride is used as an additive. The weight ratio is cellulose: maleic anhydride = 2: 1. The temperature setting of zone 9 is set in the range of 30 to 150 ° C. from the input side to the discharge side, and zone 10 is set to 150 ° C. and kneading is performed. The melting point of maleic anhydride is 53 ° C., and the boiling point is 202 ° C. The maleic anhydride is in solid form at the inlet 5 and changes to liquid form in the zone 9. In zone 9, the esterification reaction proceeds with maleic anhydride in the liquid state in the cellulose. Excess maleic anhydride is separated into resin and liquid state at zone 11 resin pressure. As a result, maleic anhydride in a liquid state is separated and discharged from the outlet 6. Thereafter, the cellulose in which the esterification reaction has proceeded is kneaded with the PP resin, and discharged from the discharge port 8 as a cellulose composite material. At this time, the input ratio is adjusted so that the content ratio of PP resin and cellulose in the final composite material is 85:15.

(Example 2)
In the same manner as in Example 1, the resin type is the same, and succinic anhydride is used as an additive, and it is blended so that the weight ratio of cellulose: succinic anhydride is 3: 1. The melting point of succinic anhydride is 119 ° C. and the boiling point is 261 ° C. The succinic anhydride is in solid form at the inlet 5 and changes to liquid form in the zone 9. Other than that is the same as that of the first embodiment.

(Example 3)
As in the first and second embodiments, a third embodiment using the twin-screw kneading device 1 of FIG. 1 will be described. As a PP resin, BC03B (manufactured by Japan Polypropylene Corporation) is introduced from the inlet 7. The temperature of the zone 11 is set to 150 to 200 ° C. from the inlet 7 to the outlet 8 and the resin is kneaded. After it is confirmed that the resin is discharged from the discharge port 8 and the resin pressure of the cylinder 4 in the zone 11 is sufficiently boosted, the cellulose and the additive are introduced into the inlet 5. Theorasu FD-101 (made by Asahi Kasei Chemicals Corporation) is used as a cellulose powder. Liquid paraffin (P-350P manufactured by Moresco Inc.) is used as an additive. The weight ratio is cellulose: liquid paraffin = 4: 1. The temperature setting of the zone 9 is set in the range of 120 to 150 ° C. from the input side to the discharge side, and the zone 10 is set at 150 ° C., and kneading is performed. Cellulose is plasticized in zone 9 by liquid paraffin in a liquid state. The surplus liquid paraffin is separated into the resin and the liquid state at the resin pressure of the zone 11, and the liquid paraffin is separated and discharged as the liquid state from the discharge port 6. Thereafter, the plasticized cellulose is kneaded with the PP resin and discharged from the discharge port 8 as a cellulose composite material. At this time, the input ratio is adjusted so that the content ratio of PP resin and cellulose in the final composite material is 90:10.

(Example 4)
In the same manner as in Example 3, the resin type is the same, and decane is used as an additive, and it is blended so that the weight ratio of cellulose: decane is 3: 1. Other than that is the same as that of the first embodiment.

(Example 5)
As in the first to fourth embodiments, a fifth embodiment using the twin-screw kneading device 1 of FIG. 1 will be described. As a PP resin, BC03B (manufactured by Japan Polypropylene Corporation) is introduced from the inlet 7. The temperature of the zone 11 is set to 150 to 200 ° C. from the inlet 7 to the outlet 8 and the resin is kneaded. After it is confirmed that the resin is discharged from the discharge port 8 and the resin pressure of the cylinder 4 in the zone 11 is sufficiently boosted, the cellulose and the additive are introduced into the inlet 5. Theorasu FD-101 (made by Asahi Kasei Chemicals Corporation) is used as a cellulose powder. As the additives, succinic anhydride and liquid paraffin (P-350P, manufactured by Moresco) are used. The weight ratio is cellulose: succinic anhydride: liquid paraffin = 4: 1: 1. The temperature setting of the zone 9 is set in the range of 120 to 150 ° C. from the input side to the discharge side, and the zone 10 is set at 150 ° C., and kneading is performed. In the zone 9, esterification is promoted by succinic anhydride in a liquid state in zone 9, and plasticization proceeds by liquid paraffin. Thereafter, the excess succinic anhydride and liquid paraffin in the liquid state are separated into the resin and the liquid state at the resin pressure of the zone 11, and the succinic anhydride and the liquid paraffin are in the liquid state from the outlet 6 Separated and discharged. Thereafter, the esterified and plasticized cellulose is kneaded with the PP resin and discharged from the outlet 8 as a cellulose composite material. At this time, the input ratio is adjusted so that the content ratio of PP resin and cellulose in the final composite material is 85:15.
(Comparative example 1)
As in Example 1, BC03B (made by Nippon Polypropylene Corp.) is introduced as a PP resin from the inlet 7 and nothing is introduced from the inlet 5, and only the PP resin is kneaded. The temperature conditions and the like are the same as in the first embodiment.
(Comparative example 2)
As in Comparative Example 1, BC03B (manufactured by Nippon Polypropylene Corporation) is introduced as a PP resin from the inlet 7 and only cellulose powder is introduced from the inlet 5 and kneaded with the PP resin. No dibasic acid anhydride and no plasticizer are charged. The temperature conditions and the like are the same as in the first embodiment.

  Table 1 shows the physical property results of the ISO test obtained using the materials obtained in Examples 1 to 5 and Comparative Examples 1 and 2.

比較例１に対し、比較例２では、強度、曲げ弾性率はあまり差がないものの、衝撃値が大きく低下している。これは混練したセルロースが微サイズ化分散されていないため、あるいは低アスペクト化粉砕されているため、いわゆる異物混練物としての影響が大きく、衝撃値の低下がみられたものと思われる。

Compared with Comparative Example 1, in Comparative Example 2, although the strength and the bending elastic modulus do not differ much, the impact value is greatly reduced. This is thought to be because the effect of the so-called foreign matter kneaded material is large and the impact value is reduced because the kneaded cellulose is not finely divided and dispersed, or reduced in aspect ratio and pulverized.

  On the other hand, in Examples 1 to 5, the physical properties are improved not only in the tensile strength but also in the flexural modulus and the impact value. It is considered that the micronization of cellulose proceeds by the esterification reaction and the plasticization reaction, and the physical properties are improved as a composite material with the PP resin. In particular, in Example 5 in which fibrillation by esterification and de-sparseness seems to be the best, it was found that about 30% improvement in physical properties can be obtained relative to Comparative Example 1.

  As described above, by using the method for producing a composite material containing cellulose according to the present embodiment, cellulose is processed in a single step and without processing using an apparatus different from one another in multiple steps. It is possible to efficiently produce a composite material in which cellulose is finely sized at a high aspect ratio, simply by using only one device and charging only the resin and the additive. Therefore, the resin function can be improved at low cost, and it can be applied to resin casings of home appliances and interior parts such as automobiles.

Reference Signs List 1 twin-screw kneading device 2 motor 3 screw 4 cylinder 5 inlet 6 outlet 7 inlet 8 outlet 12 seal ring

Claims (4)

Adding an additive to a material containing cellulose, chemically modifying and / or disentangling,
Separating and removing at least a portion of the surplus additive material from cellulose in which at least a portion of the cellulose is chemically modified and / or disintegrated by the additive material;
A process for producing a composite material containing cellulose, comprising the step of kneading the resin and the cellulose chemically modified and / or disintegrated by the additive. The additive added to the material containing cellulose is in a solid state at room temperature in the chemically modifying step, and in a liquid state in a step of separating and removing at least a part of the surplus additive. A method of producing a composite material comprising the cellulose according to claim 1. In the step of separating and removing at least a part of the surplus additive material, the surplus additive material is separated from the chemically modified and / or disintegrated cellulose by using a pressure difference with the next process. The manufacturing method of the composite material containing the cellulose as described in 1 or 2. The method for producing a composite material containing cellulose according to any one of claims 1 to 3, wherein the additive used in the step of chemically modifying esterifies a hydroxyl group of cellulose.

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