JP5656086B2 - Method for producing polymer composition and method for producing additive for polymer composition - Google Patents

Description

  The present invention relates to a method for producing a polymer composition containing cellulose fibers. Moreover, it is related with the manufacturing method of the additive for polymer compositions used for manufacture of such a polymer composition.

  Conventionally, a method of adding carbon black, silica, or the like to a polymer composition has been widely used as a means for enhancing the reinforcement of a molded product made of a polymer composition such as a rubber molded product or a resin molded product. In recent years, in addition to mechanical properties, molded articles made of polymer compositions are also required to be lighter and reduce environmental impact. In response to such demands, a method has been proposed in which a molded article is reduced in weight or an environmental load is reduced by using a polymer composition containing cellulose fibers. Especially, it is known that the cellulose fiber whose fiber diameter is thinner than a normal cellulose fiber is excellent in the effect which improves a reinforcement property. Fibers with a small fiber diameter are called “cellulose nanofibers” and are produced by fibrillating cellulose fibers.

  However, since cellulose fibers having a small fiber diameter are much more likely to aggregate than cellulose fibers having a normal fiber diameter, it has been difficult to uniformly disperse them in the polymer composition. If the cellulose fibers are not uniformly dispersed, the effect of improving the reinforcing property cannot be obtained.

  Patent Document 1 describes a masterbatch production method in which an aqueous dispersion of short fibers having an average diameter of less than 0.5 μm and a rubber latex are stirred and mixed, and water is removed from the mixture. As short fibers used at this time, fibrillated cellulose fibers, aramid short fibers and the like are described. In Patent Document 1, according to the above-described method, a master batch in which short fibers are uniformly dispersed in rubber is obtained. By using such a master batch, a balance between rubber reinforcement and fatigue resistance is obtained. It is described that a rubber composition can be obtained. However, in this method, it is necessary to remove a large amount of water after mixing an aqueous dispersion of rubber latex and short fibers. Removal of water has been a problem because it took a long time or special equipment had to be used. In addition, the cost of treating the removed water has increased. Furthermore, in this method, the usable polymer is limited to rubber latex.

  In Patent Document 2, a pulp is added to a dispersion containing 0.5 to 15 wt% of a surfactant and 0.5 to 20 wt% of a softening agent, stirred, and then dehydrated and dried. A method for dispersing pulp made of cellulose fibers to be blended therein is described. Patent Document 2 describes that a rubber composition having excellent pulp dispersibility can be obtained by adding a softening agent such as oil in addition to a surfactant. However, Patent Document 2 does not describe any method for dispersing cellulose fibers having a small fiber diameter.

  In Patent Document 3, the process oil and / or plasticizer is mixed with the process oil and / or the plasticizer by putting the process oil and / or the plasticizer and the short fiber into a closed mixer having a smaller capacity than the closed mixer used in the main kneading. A method for producing a short fiber-containing rubber is described in which after a surface-coated short fiber is obtained, a kneaded material containing the short fiber and a base rubber is subjected to main kneading using a closed kneader. In Patent Document 3, by using a small hermetic mixer, the surface of the short fiber can be obtained even if the amount of process oil and / or plasticizer is small (for example, 50 parts by weight or less with respect to 100 parts by weight of the short fiber). It is described that it is possible to coat uniformly with process oil and / or plasticizer. And, since the kneaded material containing the base rubber and the short fibers surface-coated with process oil and / or plasticizer is kneaded by the closed kneader, the short fibers can be uniformly dispersed in the base rubber. Has been. However, Patent Document 3 does not describe any use of cellulose fibers having a small fiber diameter and dispersed in water.

No. 2006-206864 2008-274064 publication 2009-73878

  The present invention has been made to solve the above-mentioned problems, and provides a simple method for producing a polymer composition that can easily provide a molded article having excellent reinforcing properties, light weight, and low environmental load. It is intended to do. Moreover, it aims at providing the manufacturing method of the additive for polymer compositions used for manufacture of such a polymer composition.

The above-mentioned problem is a cellulose having an average fiber diameter of 2 to 1000 nm and an average fiber length of 0.1 to 1000 μm and a weight ratio W (water / cellulose fiber) of water of 50/50 to 99/1. The obtained water mixture, a softener and / or a plasticizer, and a water-containing mixture containing a surfactant are heated to remove water in the water-containing mixture to obtain a dry mixture. This is solved by providing a method for producing a polymer composition in which a dry mixture is added to a base polymer.

  At this time, the weight ratio (softener and plasticizer / cellulose fiber) of the total of the softener and plasticizer to the cellulose fiber in the dry mixture is 5/95 to 99/1, and the polymer composition It is preferable that the content of the cellulose fiber is 0.01 to 20% by weight. It is also preferable that the moisture content of the dry mixture is 40% by weight or less. It is also preferred to obtain the dry mixture by heating the water-containing mixture to remove water in the water-containing mixture and then further removing excess softener and / or plasticizer.

The above-mentioned problem is a cellulose having an average fiber diameter of 2 to 1000 nm and an average fiber length of 0.1 to 1000 μm and a weight ratio W (water / cellulose fiber) of water of 50/50 to 99/1. Provided is a method for producing an additive for a polymer composition, which comprises heating an aqueous mixture containing an aqueous dispersion of fibers, a softening agent and / or a plasticizer, and a surfactant to remove water in the aqueous mixture. Can also be solved. At this time, it is preferable that the weight ratio (softener and plasticizer / cellulose fiber) of the total of the softener and plasticizer and the cellulose fiber is 5/95 to 99/1.

  According to the method for producing a polymer composition of the present invention, a polymer composition in which cellulose fibers having a smaller fiber diameter than normal cellulose fibers are uniformly dispersed can be easily obtained. A molded product produced using such a polymer composition has excellent reinforcing properties and is lightweight. Moreover, since the cellulose fiber is a plant-derived material, the environmental load is small. Moreover, according to the manufacturing method of the additive for polymer compositions of this invention, the additive for polymer compositions which can be used for manufacture of such a polymer composition can be obtained simply.

  The present invention relates to a water-containing mixture containing an aqueous dispersion of a cellulose fiber having an average fiber diameter of 2 to 1000 nm and an average fiber length of 0.1 to 1000 μm, a softener and / or a plasticizer, and a surfactant. Is a method for producing a polymer composition in which a dry mixture is obtained by heating water to remove water in the water-containing mixture, and then the obtained dry mixture is added to a base polymer.

  In the production method of the present invention, as a method for containing cellulose fibers in a polymer composition, a softener and / or a plasticizer usually used for molding a polymer composition and a dry mixture containing cellulose fibers are used as a base. A method of adding to the polymer is used. By adding a softener and / or a plasticizer together with the cellulose fiber to the base polymer, the cellulose fiber can be dispersed in the polymer composition. And in order to disperse | distribute a cellulose fiber uniformly in a polymer composition, it is very important that the cellulose fiber does not aggregate in the said dry mixture. As a result of intensive studies, the present inventors have heated a water-containing mixture containing an aqueous dispersion of cellulose fibers, a softener and / or a plasticizer, and a surfactant to remove water in the water-containing mixture. Thus, it has been found that aggregation of cellulose fibers is effectively suppressed.

  In the production method of the present invention, an aqueous dispersion of cellulose fiber is used as the raw material cellulose fiber. The cellulose fiber has an average fiber diameter of 2 to 1000 nm and an average fiber length of 0.1 to 1000 μm. Cellulose fibers having such a small fiber diameter are very easy to aggregate, and once aggregated, it is very difficult to understand again. On the other hand, cellulose fibers having a small fiber diameter are easily dispersed in water. Therefore, handling of the cellulose fibers is facilitated by using the aqueous dispersion of cellulose fibers. Further, among cellulose fibers that are generally distributed and have a small fiber diameter, many are aqueous dispersions of cellulose fibers. This point is also one of the reasons why an aqueous dispersion of cellulose fibers is used as a raw material for cellulose fibers in the present invention.

  When the average fiber diameter and the average fiber length of the cellulose fibers are within the above ranges, the reinforcing property of a molded product obtained by molding the polymer composition of the present invention is improved.

  Cellulose fibers having an average fiber diameter of less than 2 nm are difficult to obtain by ordinary methods and are not practical for industrial use. The average fiber diameter of the cellulose fibers is preferably 5 nm or more, and more preferably 10 nm or more. On the other hand, when the average fiber diameter of the cellulose fiber exceeds 1000 nm, the reinforcing property of the obtained molded product is lowered. The average fiber diameter of the cellulose fiber is preferably 500 nm or less. In addition, the average fiber diameter in this invention is the number average fiber diameter computed by microscope observation.

  When the average fiber length of the cellulose fiber is less than 0.1 μm, the reinforcing property of the obtained molded product is lowered. The average fiber length of the cellulose fibers is preferably 1 μm or more, more preferably 10 μm or more, and further preferably 50 μm or more. On the other hand, when the average fiber length of the cellulose fibers exceeds 1000 μm, the cellulose fibers aggregate in the dry mixture. In this case, it is difficult to obtain a polymer composition in which cellulose fibers are uniformly dispersed, and the reinforcing property of the obtained molded product is lowered. The average fiber length is preferably 800 μm or less. In addition, the average fiber length in this invention is the number average fiber diameter computed by microscope observation.

  The ratio of the average fiber length to the average fiber diameter (average fiber length / average fiber diameter) of the cellulose fibers is preferably 50 or more, and more preferably 100 or more. When the ratio of the average fiber length to the average fiber diameter (average fiber length / average fiber diameter) is less than 50, the reinforcing property of the obtained molded product may be lowered.

  The cellulose fiber used for this invention will not be specifically limited if it has the above-mentioned average fiber diameter and average fiber length, A general fibrillated cellulose fiber can be used conveniently. Examples of the raw material for the fibrillated cellulose fiber include wood, firewood, bamboo, bagasse, firewood, firewood, and rice husk. The fibrillation can be performed by applying a mechanical shearing force to the obtained cellulose fiber using a beater, a homogenizer, or the like. Moreover, fibrillation of cellulose fibers can also be performed by chemical treatment.

  The weight ratio W (water / cellulose fiber) of the cellulose fiber to water in the aqueous dispersion used in the present invention is not particularly limited, but is preferably 50/50 to 99/1. When the weight ratio W is less than 50/50, the cellulose fibers may aggregate in water. The weight ratio W is more preferably 70/30 or more, and further preferably 80/20 or more. On the other hand, when the weight ratio W exceeds 99/1, the amount of water to be removed from the water-containing mixture becomes very large, so that energy required for drying increases and productivity may decrease. It is more preferable that the weight ratio W is 95/5 or less.

  The aqueous dispersion of cellulose fibers used in the present invention may contain various additives other than cellulose fibers and water as long as the effects of the present invention are not impaired. The content of additives other than cellulose fibers and water is usually 10% by weight or less.

  The dry mixture only needs to contain at least one of a softener and a plasticizer. Softeners and plasticizers promote the dispersion of cellulose fibers when the dry mixture is added to the base polymer. In addition, since the softener and plasticizer used at this time are generally used when molding the polymer composition, the physical properties of the molded product are not deteriorated, and the raw material cost is increased. Nor.

  The softener used in the present invention is not particularly limited, and various softeners generally used when molding a polymer composition can be used. For example, process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, petroleum softener such as petroleum jelly, fatty oil softener such as castor oil, linseed oil, rapeseed oil, coconut oil, tall oil, sub, beeswax , Waxes such as carnauba wax and lanolin, and fatty acids such as linoleic acid, palmitic acid, stearic acid, and lauric acid.

  The plasticizer used in the present invention is not particularly limited, and various plasticizers generally used when molding a polymer composition can be used. For example, phthalic acid esters such as dibutyl phthalate (DBP) and dioctyl phthalate (DOP), adipic acid esters such as dioctyl adipate (DOA), sebacic acid esters such as dioctyl sebacate (DOS), and phosphoric acids such as tricresyl phosphate Examples include esters.

  The surfactant used in the present invention is not particularly limited, and for example, nonionic surfactants, anionic surfactants, cationic surfactants and amphoteric surfactants can be used.

  Examples of the nonionic surfactant used in the present invention include polyoxyalkylene alkyl ether, polyoxyalkylene alkylphenyl ether, sorbitan fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, glycerin fatty acid ester, polyoxyalkylene hydrogenated castor oil, and the like. It is done. Anionic surfactants include carboxylates such as fatty acids; sulfates such as alkyl sulfates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl phenyl ether sulfates, polyoxyethylene styrenated phenyl ether sulfates Sulfonic acid salts such as alkylbenzene sulfonate, alkylnaphthalene sulfonate, alkyl sulfonate, and α-olefin sulfonic acid; and phosphate ester salts such as alkyl phosphate and polyoxyethylene alkyl ether phosphate It is done. Examples of the cationic surfactant include amine salts and quaternary ammonium salts. Examples of amphoteric surfactants include carboxybetaine and sulfobetaine. Among these, nonionic surfactants are preferable in view of the influence on vulcanization.

  A water-containing mixture containing the above-described cellulose fiber aqueous dispersion, softener and / or plasticizer, and surfactant is heated to remove water in the water-containing mixture to obtain a dry mixture. As described above, the most characteristic feature of the production method of the present invention is to remove water in the water-containing mixture by heating and evaporating the water. Thereby, a dry mixture in which the cellulose fibers are not aggregated is obtained. Cellulose fibers, softeners and plasticizers are not so high in affinity, and cellulose fibers having a small fiber diameter are very likely to aggregate. Therefore, even if the aqueous dispersion of cellulose fiber and the softener and / or plasticizer are physically stirred, the cellulose fiber remains dispersed in water, and the cellulose fiber and the softener and / or plasticizer are It is thought that they are separated. From such a thing, it is thought that a cellulose fiber will aggregate if water is removed by general methods, such as centrifugation. On the other hand, as a result of intensive studies, the present inventors have heated the water-containing mixture containing a surfactant in addition to an aqueous dispersion of cellulose fibers, a softener and / or a plasticizer, and the water-containing mixture. It has been found that by removing water in the mixture, a dry mixture in which the cellulose fibers are not aggregated can be obtained. It is quite surprising that the aggregation of cellulose fibers can be prevented by such a simple method. Although the detailed mechanism at this time is not clear, it is thought that the softening agent and the plasticizer enter between the cellulose fibers and the aggregation of the cellulose fibers is suppressed when the water in the water-containing mixture evaporates. At this time, it is considered that the surfactant promotes the entry of the softener and the plasticizer between the cellulose fibers by expressing the effect of increasing the affinity between the cellulose fiber and the softener and the plasticizer. It is done.

  The water-containing mixture is obtained by mixing an aqueous dispersion of cellulose fibers, a softener and / or a plasticizer, and a surfactant. At this time, the order of mixing the components is not particularly limited. From the viewpoint of further suppressing the aggregation of the cellulose fibers, after previously adding a surfactant to at least one of the aqueous dispersion of the cellulose fibers or the softener and / or the plasticizer, the aqueous dispersion of the cellulose fibers, The above water-containing mixture is obtained by mixing a softener and / or a plasticizer, or a water-containing mixture of cellulose fibers, a softener and / or a plasticizer, and a surfactant are mixed at the same time to obtain a water-containing mixture in the previous period. It is preferred to obtain.

  The mixing ratio of the cellulose fiber aqueous dispersion, softener and / or plasticizer, and surfactant is not particularly limited, but the total of the softener and plasticizer and the cellulose in the aqueous dispersion are not limited. It is preferable that the blending weight ratio of the fibers (softener and plasticizer / cellulose fiber) is 5/95 to 99/1. When the blending weight ratio (softener and plasticizer / cellulose fiber) is less than 5/95, the cellulose fiber may aggregate in the dry mixture. On the other hand, when the blending weight ratio (softener and plasticizer / cellulose fiber) exceeds 99/1, the amount of cellulose fiber that can be contained in the polymer composition becomes too small, and reinforcement by cellulose fiber. The effect of improving the property may be insufficient. The blending weight ratio (softener and plasticizer / cellulose fiber) is more preferably 95/5 or less.

  When kneading the obtained dry mixture and the base polymer, the blending weight ratio (softener and plasticizer / cellulose fiber) is 30/70 or more from the viewpoint that shear force is easily applied to the master batch and kneading is facilitated. It is preferable that it is 50/50 or more, and it is further more preferable that it is 65/35 or more.

  From the viewpoint of increasing the content of cellulose fiber without increasing the content of softener and / or plasticizer in the polymer composition, the blending weight ratio (softener and plasticizer / cellulose fiber) Is less than 70/30, more preferably less than 65/35, even more preferably less than 50/50, and particularly preferably less than 30/70. is there.

  When mixing the aqueous dispersion, softener and / or plasticizer of the cellulose fiber, and the surfactant, the mixing weight ratio of the surfactant and the cellulose fiber in the aqueous dispersion (surfactant / cellulose fiber) is 0. It is preferable that it is 1 / 99.9 to 67/33. When the blending weight ratio (surfactant / cellulose fiber) is less than 0.1 / 99.9, the cellulose fibers in the dry mixture may easily aggregate. It is more preferable that the blending weight ratio (surfactant / cellulose fiber) is 1/99 or more. On the other hand, when the blending weight ratio (surfactant / cellulose fiber) exceeds 67/33, the content of the surfactant in the polymer composition is excessively increased, which may adversely affect the resulting molded product. There is. The blending weight ratio (surfactant / cellulose fiber) is more preferably 50/50 or less.

  The timing which heats the said water-containing mixture is not specifically limited. For example, an aqueous dispersion of cellulose fibers, a softener and / or a plasticizer, and a surfactant can be mixed and heated in parallel. At this time, at least one of the cellulose fiber aqueous dispersion, softener and / or plasticizer, and surfactant is preheated, and the remaining components are added to the heated component. It is more preferable that a mixture of a softener and / or a plasticizer and a surfactant is heated in advance, and an aqueous dispersion of cellulose fibers is further preferably added to the heated mixture. It is. On the other hand, after mixing of the aqueous dispersion of cellulose fibers, the softener and / or the plasticizer, and the surfactant, the obtained water-containing mixture can be heated.

  Although the temperature of the said water-containing mixture at the time of heating the said water-containing mixture is not specifically limited, It is suitable to heat so that it may become 100 degreeC or more. By boiling water at such a temperature, the cellulose fibers are more difficult to aggregate.

  It is preferable to perform mixing of the cellulose fiber aqueous dispersion, softener and / or plasticizer, surfactant, and water-containing mixture while stirring. Thereby, it becomes difficult for a cellulose fiber to aggregate further.

  The method for mixing the cellulose fiber aqueous dispersion, softener and / or plasticizer, and surfactant and heating the water-containing mixture are not particularly limited, and a commonly used stirrer with a heating function and exhaust function. It can be performed by using a kneader or the like. Examples of these stirrers and kneaders include Henschel mixers, screw extruders, planetary stirrers (automatic / revolving stirrers), Brabenders (tangential closed kneaders), and the like.

  It is preferable to obtain a dry mixture by further removing excess softener and / or plasticizer after heating the water-containing mixture to remove water in the water-containing mixture. Thereby, since the content of the cellulose fiber can be increased without increasing the content of the softening agent and / or the plasticizer in the polymer composition, the selection range of the component ratio of the polymer composition is expanded. The excess softener and / or plasticizer can be removed, for example, by removing the liquid portion having a high ratio of softener and / or plasticizer in the dry mixture by pressing or the like.

  The moisture content of the dry mixture thus obtained is preferably 40% by weight or less. When the water content of the dry mixture exceeds 40% by weight, the water content of the polymer composition becomes too high, and foaming due to water vapor occurs at the time of molding, resulting in poor appearance or reduced mechanical properties. There is a risk. More preferably, the moisture content of the dry mixture is not more than 35% by weight.

  The water to cellulose fiber weight ratio D (water / cellulose fiber) in the dry mixture is preferably 90/10 or less, and more preferably 75/25 or less. When the weight ratio D exceeds 90/10, the water content of the polymer composition becomes too high, and foaming due to water vapor occurs at the time of molding, which may cause the appearance to deteriorate or the mechanical properties to deteriorate. .

  It is preferable that the weight ratio W (D / W) of the cellulose fibers and water in the water-containing mixture and the weight ratio D of the cellulose fibers and water in the dry mixture is 0.8 or less. In this case, the cellulose fibers are less likely to aggregate in the dry mixture. The ratio (D / W) is more preferably 0.6 or less.

  The total weight of the softener and plasticizer in the dry mixture and the weight ratio of the cellulose fiber (softener and plasticizer / cellulose fiber) is not particularly limited, but is preferably 5/95 to 99/1. When the weight ratio (softener and plasticizer / cellulose fiber) is within such a range, the cellulose fiber is more easily dispersed in the polymer composition. When the weight ratio (softener and plasticizer / cellulose fiber) in the dry mixture is less than 5/95, the amount of the softener and plasticizer relative to the cellulose fiber is too small. There exists a possibility that the dispersibility of a cellulose fiber may fall. On the other hand, when the weight ratio (softener and plasticizer / cellulose fiber) in the dry mixture exceeds 99/1, the amount of cellulose fiber that can be contained in the polymer composition is too small, There exists a possibility that the effect which improves the reinforcement by a cellulose fiber may become inadequate. More preferably, the weight ratio (softener and plasticizer / cellulose fiber) is 95/5 or less. The sum of the softener and plasticizer in the dry mixture and the weight ratio of cellulose fibers (softener and plasticizer / cellulose fibers) is usually the same as the weight ratio in mixing them, as described above, When the excess softener and / or plasticizer is removed, the weight ratio is smaller than that when mixing them.

  When kneading the obtained dry mixture and the base polymer, the weight ratio (softener and plasticizer / cellulose fiber) in the dry mixture is determined from the viewpoint that shear force is easily applied to the master batch and kneading is facilitated. It is preferably 30/70 or more, more preferably 50/50 or more, and further preferably 65/35 or more.

  From the viewpoint of increasing the content of the cellulose fiber without increasing the content of the softener and / or plasticizer in the polymer composition, the weight ratio in the dry mixture (softener and plasticizer) / Cellulose fiber) is preferably 70/30 or less, more preferably less than 65/35, even more preferably less than 50/50, and less than 30/70. Is particularly preferred.

  The weight ratio of the surfactant to the cellulose fiber (surfactant / cellulose fiber) in the dry mixture is not particularly limited, but is preferably 0.1 / 99.9 to 67/33. When the weight ratio of the surfactant and the cellulose fiber (surfactant / cellulose fiber) is less than 0.1 / 99.9, the dispersibility of the cellulose fiber in the dry mixture may be lowered. The weight ratio (surfactant / cellulose fiber) is more preferably 1/99 or more. On the other hand, when the weight ratio (surfactant / cellulose fiber) exceeds 67/33, the content of the surfactant in the polymer composition is excessively increased, which may adversely affect the resulting molded product. is there. The weight ratio (surfactant / cellulose fiber) is more preferably 50/50 or less. The weight ratio of surfactant to cellulose fiber in the dry mixture (surfactant / cellulose fiber) is usually the same as the weight ratio at which it is mixed, and as described above, excess softener and / or When the plasticizer is removed, depending on the removal method, the weight ratio may be smaller than the mixing ratio.

  The dry mixture may contain other additives as long as the effects of the present invention are not impaired. Examples of such additives include fillers other than cellulose fibers, adhesion imparting agents, and anti-aging. Such an additive may be added when the aqueous dispersion of cellulose fiber, the softener and / or the plasticizer, and the surfactant are mixed, or may be preliminarily contained therein. The content of such additives is preferably less than 50% by weight.

  When the ratio of the softening agent and / or plasticizer to the cellulose fiber in the dry mixture is high, the dry mixture contains a solid portion in which the cellulose fibers are dense and a liquid having a high ratio of the softening agent and / or the plasticizer. Part may occur. In this invention, even if it is a case where the dry mixture which has such a solid part is used, the polymer composition in which the cellulose fiber was disperse | distributed uniformly can be obtained. Cellulose fibers are densely packed in the solid portion at this time, but it is considered that a softener and / or a plasticizer is present between the cellulose fibers. Therefore, when such solid content is added to the base polymer, it is considered that the softener and / or plasticizer present between the cellulose fibers promotes the dispersion of the cellulose fibers.

  On the other hand, when the ratio of the softener and / or the plasticizer to the cellulose fiber in the dry mixture is low, a powdery dry mixture may be obtained. In the present invention, even when the dry mixture is such a powder, a polymer composition in which cellulose fibers are uniformly dispersed can be obtained. At this time, it is considered that the softening agent and / or the plasticizer is attached to the cellulose fiber, and thus the aggregation of the cellulose fiber is considered to be suppressed. When such a dry mixture is added to the base polymer, it is considered that the softener and / or plasticizer attached to the cellulose fiber promotes the dispersion of the cellulose fiber.

  A polymer composition is obtained by mixing the dry mixture with a base polymer. As described above, when the dry mixture is mixed with the base polymer, the cellulose fibers are uniformly dispersed in the base polymer by the action of the softener and / or the plasticizer in the dry mixture. Therefore, such a dry mixture can be suitably used as an additive for a polymer composition for dispersing and containing cellulose fibers.

  The base polymer used in the present invention is not particularly limited. The base polymer may be rubber or resin.

  Examples of the rubber used as the base polymer include ethylene-propylene-diene terpolymer rubber (EPDM), acrylonitrile-butadiene copolymer rubber (NBR), chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), ethylene- Propylene copolymer rubber (EPM), acrylic rubber (ACM), hydrin rubber, styrene-butadiene copolymer rubber (SBR), isobutylene-isoprene copolymer rubber (IIR), natural rubber (NR), isoprene rubber (IR), butadiene Examples thereof include rubber (BR), urethane rubber, silicone rubber, and fluorine rubber. These may be used alone or in combination.

  The resins used as the base polymer include polyvinyl chloride resin (PVC), polyethylene resin (PE), polypropylene resin (PP), polyvinylidene chloride resin, polystyrene resin (PS), polyvinyl alcohol resin (PVA), and polyvinyl acetate. Examples thereof include resin (PVAc), acrylic resin, ethylene-vinyl acetate copolymer resin (EVA), polyester, polyamide (PA), and polylactic acid (PLA). These may be used alone or in combination. A thermoplastic elastomer can also be used.

  A method for adding the dry mixture to the base polymer is not particularly limited. Examples thereof include a method of kneading the dry mixture and the base polymer using an open roll, a Banbury mixer, a kneader, a screw extruder, or the like.

  Although content of the said cellulose fiber in the said polymer composition is not specifically limited, It is suitable that it is 0.01-20 weight%. When the content of the cellulose fiber in the polymer composition is less than 0.01% by weight, the reinforcing property of the obtained molded product may be lowered. The content of the cellulose fiber is more preferably 0.1% by weight or more. On the other hand, when the content of the cellulose fiber in the polymer composition exceeds 20% by weight, the obtained molded product may be fragile. The content of the cellulose fiber is more preferably 15% by weight or less.

  The total weight of the softener and plasticizer in the polymer composition and the weight ratio of the cellulose fiber (softener and plasticizer / cellulose fiber) are not particularly limited, but the softener and plasticizer in the dry mixture described above are not limited. It is preferable that the total amount of the agents is the same as the range of the weight ratio of cellulose fibers (softener and plasticizer / cellulose fibers). The softener, plasticizer and cellulose fiber in the dry mixture will all be included in the polymer composition. The content of the softener and / or plasticizer in the polymer composition may be adjusted by adjusting the content of the softener and / or plasticizer in the dry mixture, and / or the softener and / or This may be done by adding a plasticizer directly to the base polymer.

  The weight ratio of the surfactant and the cellulose fiber in the polymer composition (surfactant / cellulose fiber) is not particularly limited, but the weight ratio of the surfactant and the cellulose fiber in the dry mixture described above (interface) The range is preferably the same as the range of (active agent / cellulose fiber). All the surfactants in the dry mixture will be contained in the polymer composition.

  The polymer composition may contain various commonly used additives as long as the effects of the present invention are not impaired. Examples of such additives include a vulcanization or crosslinking agent, a vulcanization or crosslinking accelerator, a filler, a plasticizer, a softening agent, and an antiaging agent. Such an additive may be added simultaneously with the addition of the dry mixture, or may be added by being previously contained in at least one of the base polymer and the dry mixture.

  In the polymer composition of the present invention thus obtained, cellulose fibers having a small fiber diameter are uniformly dispersed. Therefore, a molded product obtained by molding such a polymer composition is lightweight and has excellent reinforcing properties. Furthermore, since plant-derived cellulose fibers are used, the environmental burden is reduced. Therefore, the polymer composition of the present invention can be used as a material for various molded articles. For example, it can be suitably used as a material for molded articles for automobiles such as air intake hoses, water hoses and dust covers, and rubber sheets for the civil engineering industry.

  Hereinafter, the present invention will be described using examples. The measurement methods and evaluation methods described in the examples were performed according to the following methods.

[Hardness test]
The durometer hardness (standard hardness) was measured according to JIS K6253 (vulcanized rubber and thermoplastic rubber—how to determine hardness). A type A durometer was used for the measurement. As a test piece, a molded product having a length of 50 mm, a width of 50 mm, and a thickness of 6 mm was used.

[Tensile test]
Tensile tests were conducted according to JIS K6251 (vulcanized rubber and thermoplastic rubber—how to obtain tensile properties), and tensile strength, tensile stress (modulus) and elongation were measured. A 2 mm thick JIS K6251 standard dumbbell-shaped No. 5 shaped product was used as a test piece. The tensile test was performed such that the roll rotation direction when kneaded with an open roll was the tensile direction.

Example 1
After adding 176 g of a softener (naphthene oil) and 4 g of a nonionic surfactant [polyoxyethylene (10) octylphenyl ether] to the beaker, using a magnetic stirrer with a hot plate (set temperature 110 ° C.) The mixture was stirred with heating. After the temperature of the mixture in the beaker reaches about 110 ° C., an aqueous dispersion of cellulose fibers (“Serish KY100G” manufactured by Daicel Chemical Industries, Ltd., average fiber diameter 100 nm, average fiber length 500 μm, cellulose fiber content 10% by weight The water content was 90% by weight). The aqueous dispersion of cellulose fibers was added little by little, and a total of 200 g was added. Heating and stirring of the mixture in the beaker was continued while adding the aqueous dispersion of cellulose fibers. Even after the addition of the aqueous dispersion of cellulose fibers was completed, heating and stirring of the mixture in the beaker were continued for about 30 minutes, and then heating and stirring were stopped, and the mixture in the beaker was cooled to room temperature. Thus, 250 g of a dry mixture (polymer composition additive) having a water content of 20% by weight was obtained. The ratio of each component in the dry mixture is shown in Table 1. The dry mixture had a solid content of dense cellulose fibers and a liquid portion with a high softener ratio.

  A polymer composition was obtained by kneading the base polymer, the dry mixture and other additives using an open roll for 10 minutes. Table 1 shows the raw materials used at this time and the blending ratios thereof. The obtained polymer composition was press vulcanized at 150 ° C. for 9 minutes to form test pieces for hardness test and tensile test, respectively. Using each of the obtained test pieces, a hardness test and a tensile test were performed. Table 2 shows the results of the hardness test and the tensile test.

Example 2
In the same manner as in Example 1, a mixture containing a softener, a nonionic surfactant and cellulose fiber and having a moisture content of 20% by weight was obtained. By squeezing the mixture to remove the liquid portion in the mixture, a dry mixture having an increased cellulose fiber content ratio was obtained. The ratio of each component in the dry mixture is shown in Table 1. Using the dry mixture thus obtained, the test pieces for the hardness test and the tensile test were molded and evaluated in the same manner as in Example 1. Table 2 shows the results of the hardness test and the tensile test.

Comparative Example 1
Test pieces for a hardness test and a tensile test were respectively formed in the same manner as in Example 1 except that 18 g of a softening agent (naphthene oil) was used instead of the dry mixture. Table 1 shows the raw materials of the polymer composition and the blending ratio thereof. Using each of the obtained test pieces, a hardness test and a tensile test were performed. Table 2 shows the results of the hardness test and the tensile test.

Comparative Example 2
The raw material of the polymer composition (see Table 1) was kneaded with an open roll in the same manner as in Example 1 except that 18 g of a softening agent (naphthene oil) was used instead of the dry mixture, and then wound around the open roll. To the mixture, an aqueous dispersion of cellulose fibers (“Serisch KY100G” manufactured by Daicel Chemical Industries, Ltd.) in an amount of 2 parts by weight of cellulose fibers (solid content) with respect to 100 parts by weight of natural rubber is added. Kneading was performed. At this time, the cellulose fibers slipped on the surface of the mixture wound around the open roll, and the cellulose fibers could not be kneaded into the mixture.

Comparative Example 3
Among the raw materials shown in Table 1, those other than the aqueous dispersion of cellulose fibers ("Cerish KY100G" manufactured by Daicel Chemical Industries, Ltd.) were kneaded in a kneading mixer. On the other hand, an aqueous dispersion of cellulose fibers in an amount of 2 parts by weight of cellulose fibers (solid content) was added to 100 parts by weight of natural rubber and further kneaded. At this time, the cellulose fibers slipped on the surface of the mixture in the mixer, and the cellulose fibers could not be kneaded into the mixture.

  Molded articles (Examples 1 and 2) produced using the polymer composition of the present invention were harder than molded articles (Comparative Example 1) produced using a polymer composition containing no cellulose fiber. And the modulus increased. On the other hand, when an aqueous dispersion of cellulose fibers is directly added to the base polymer, the cellulose fibers can be kneaded regardless of the kneading method [open roll (Comparative Example 2), kneading mixer (Comparative Example 3)]. There wasn't.

Example 3
After obtaining a mixture by mixing 120 g of a plasticizer (dioctyl phthalate) and 4.8 g of a nonionic surfactant [polyoxyethylene (10) octylphenyl ether] in a stainless steel tray, the mixture was added to a sand bath. It heated using the type | mold hotplate (setting temperature 110 degreeC). After the temperature of the mixture reaches 110 ° C., a small amount of an aqueous dispersion of cellulose fibers (“Serish KY100G” manufactured by Daicel Chemical Industries, Ltd.) is added to the mixture, and the added cellulose fibers are used with a spoon. And opened. By repeating the addition of the aqueous dispersion of cellulose fibers and the opening process, a total of 120 g of the aqueous dispersion of cellulose fibers was added. The heating of the mixture was continued while adding the aqueous dispersion of cellulose fibers. Even after the addition of the aqueous dispersion of cellulose fibers was completed, heating of the mixture in the beaker was continued for about 30 minutes, and then the heating was stopped and the mixture in the beaker was cooled to room temperature. Thus, 171 g of a dry mixture (additive for polymer composition) having a water content of 20% by weight was obtained. The ratio of each component in the dry mixture is shown in Table 3. The dry mixture had a solid part with dense cellulose fibers and a liquid part with a high proportion of plasticizer.

  A polymer composition was produced using the obtained dry mixture. Table 3 shows the raw materials used and the blending ratios. The polymer composition is prepared by kneading the raw material of the polymer composition other than the vulcanizing agent in advance using a Banbury mixer and then kneading the obtained mixture and the vulcanizing agent using an open roll. I got a thing. The polymer composition was press vulcanized at 160 ° C. for 10 minutes to form a test piece for a hardness test and a tensile test, respectively. Using each of the obtained test pieces, a hardness test and a tensile test were performed. Table 4 shows the results of the hardness test and the tensile test.

Comparative Example 4
Test for hardness test and tensile test in the same manner as in Example 3 except that a plasticizer (dioctyl phthalate) was used instead of the dry mixture, and the amounts of sulfur and vulcanization accelerator were changed. Each piece was molded. Table 3 shows the raw materials of the polymer composition and the blending ratio thereof. Using each of the obtained test pieces, a hardness test and a tensile test were performed. Table 4 shows the results of the hardness test and the tensile test.

Comparative Example 5
An aqueous dispersion of cellulose fibers was added to the plasticizer in the same manner as in Example 3 except that the surfactant was not added. At this time, the cellulose fibers were aggregated and cured in a shape like “coral”. Therefore, the test piece was not molded and evaluated.

  The molded product (Example 3) produced using the polymer composition of the present invention is harder than the molded product (Comparative Example 4) produced using a polymer composition containing no cellulose fiber. Tensile strength and modulus were increased. Moreover, when the aqueous dispersion of cellulose fibers was added to the plasticizer without using a surfactant (Comparative Example 5), the cellulose fibers were aggregated.

Example 4
After obtaining a mixture by mixing 300 g of a softening agent (paraffin oil) and 12 g of a nonionic surfactant [polyoxyethylene (10) octylphenyl ether] in a stainless steel tray, the mixture was added to a sand bath hot plate. (Set temperature 110 ° C.). After the temperature of the mixture reaches 110 ° C., a small amount of an aqueous dispersion of cellulose fibers (“Cerish KY100G” manufactured by Daicel Chemical Industries, Ltd.) is added to the mixture, and the cellulose fibers are opened using a spoon. did. By repeating the addition of the cellulose fiber aqueous dispersion and the opening process, a total of 300 g of the cellulose fiber aqueous dispersion was added. The heating of the mixture was continued while adding the aqueous dispersion of cellulose fibers. Even after the addition of the aqueous dispersion of cellulose fibers was completed, heating of the mixture in the beaker was continued for about 30 minutes, and then the heating was stopped and the mixture in the beaker was cooled to room temperature. Thus, 428 g of a dry mixture (additive for polymer composition) having a water content of 20% by weight was obtained. Table 5 shows the ratio of each component in the dry mixture. The dry mixture had a solid part with dense cellulose fibers and a liquid part with a high proportion of plasticizer.

  A polymer composition was produced using the obtained dry mixture. Table 5 shows the raw materials used at this time and their ratios. The polymer composition is prepared by kneading the raw material of the polymer composition other than the vulcanizing agent in advance using a Banbury mixer and then kneading the obtained mixture and the vulcanizing agent using an open roll. I got a thing. The polymer composition was press vulcanized at 160 ° C. for 10 minutes to form a test piece for a hardness test and a tensile test, respectively. Using each of the obtained test pieces, a hardness test and a tensile test were performed. Table 6 shows the results of the hardness test and the tensile test.

Comparative Example 6
Test pieces for hardness test and tensile test were respectively formed in the same manner as in Example 4 except that a softener (paraffin oil) was used instead of the dry mixture. Table 5 shows the raw materials of the polymer composition and the blending ratio thereof. Using each of the obtained test pieces, a hardness test and a tensile test were performed. Table 6 shows the results of the hardness test and the tensile test.

  The molded product (Example 4) produced using the polymer composition of the present invention has a hardness, compared with the molded product (Comparative Example 6) produced using a polymer composition containing no cellulose fiber. Tensile strength and modulus were increased.

Example 5
8 g of softener (paraffin oil), 8 g of a nonionic surfactant [polyoxyethylene (10) octylphenyl ether] and 640 g of an aqueous dispersion of cellulose fibers (“Serisch KY100G” manufactured by Daicel Chemical Industries, Ltd.) are planetary stirred. The machine (revolving / spinning type stirrer) was added and premixed for 6 minutes at room temperature. The obtained preliminary mixture was filled in a Brabender (tangential closed kneader) and kneaded at a temperature of 160 ° C. and a rotation speed of 120 min ⁻¹ . In accordance with the decrease in the filling rate of the mixture due to evaporation of moisture, the preliminary mixture was additionally charged. After the entire amount of the preliminary mixture was charged, the kneading was terminated when the temperature in the kneader increased to 140 ° C. or higher, and the dry mixture was taken out and cooled to room temperature. Thus, 84 g of a dry mixture (polymer composition additive) having a water content of 4.6% by weight was obtained. Table 7 shows the ratio of each component in the dry mixture. The dry mixture was powdery.

  A polymer composition was prepared using the obtained dry mixture. Test pieces for a hardness test and a tensile test were formed in the same manner as in Example 4 except that the raw materials shown in Table 7 were used. Using each of the obtained test pieces, a hardness test and a tensile test were performed. Table 8 shows the results of the hardness test and the tensile test.

Example 6
A dry mixture (additive for polymer composition) was prepared in the same manner as in Example 5 except that the amount of the softening agent (paraffin oil) was different. Table 7 shows the ratio of each component in the dry mixture. The obtained dry mixture was in the form of an oily powder, and the water content was 2.5% by weight.

  Test pieces for a hardness test and a tensile test were formed in the same manner as in Example 4 except that the raw materials having the ratios shown in Table 7 were used. Using each of the obtained test pieces, a hardness test and a tensile test were performed. Table 8 shows the results of the hardness test and the tensile test.

Comparative Example 7
Test pieces for a hardness test and a tensile test were respectively formed in the same manner as in Example 5 except that a softener (paraffin oil) was used instead of the dry mixture. Table 7 shows the raw materials of the polymer composition and the blending ratio thereof. Using each of the obtained test pieces, a hardness test and a tensile test were performed. Table 8 shows the results of the hardness test and the tensile test.

  Molded articles (Examples 5 and 6) produced using the polymer composition of the present invention were harder than molded articles (Comparative Example 7) produced using a polymer composition containing no cellulose fiber. And the modulus increased.

Claims (6)

Water dispersion of cellulose fibers having an average fiber diameter of 2 to 1000 nm and an average fiber length of 0.1 to 1000 μm and a weight ratio W (water / cellulose fibers) of water of 50/50 to 99/1. After heating the water-containing mixture containing the body, the softener and / or the plasticizer, and the surfactant to remove the water in the water-containing mixture, a dry mixture is obtained, and then the obtained dry mixture is used as a base. A method for producing a polymer composition, which is added to a polymer.   In the dry mixture, the total weight of the softener and plasticizer and the weight ratio of cellulose fiber (softener and plasticizer / cellulose fiber) is 5/95 to 99/1, and in the polymer composition, The method for producing a polymer composition according to claim 1, wherein the content of the cellulose fiber is 0.01 to 20% by weight.   The method for producing a polymer composition according to claim 1 or 2, wherein the moisture content of the dry mixture is 40% by weight or less.   The weight according to any one of claims 1 to 3, wherein the water-containing mixture is heated to remove water in the water-containing mixture, and then the excess softener and / or plasticizer is further removed to obtain the dry mixture. A method for producing a combined composition. Water dispersion of cellulose fibers having an average fiber diameter of 2 to 1000 nm and an average fiber length of 0.1 to 1000 μm and a weight ratio W (water / cellulose fibers) of water of 50/50 to 99/1. The manufacturing method of the additive for polymer compositions characterized by heating the water-containing mixture containing a body, a softener, and / or a plasticizer, and surfactant, and removing the water in this water-containing mixture.   The method for producing an additive for a polymer composition according to claim 5, wherein the weight ratio of the total of the softener and the plasticizer to the cellulose fiber (softener and plasticizer / cellulose fiber) is 5/95 to 99/1.