JP2021001258A - Thermoplastic resin composition, molded body, and electrical and electronic devices - Google Patents

Abstract

To provide a thermoplastic resin composition which has good fire retardancy even when a content of a fire retardant is small and which can stably provide a molded body having good appearance and strength.SOLUTION: Provided is a thermoplastic resin composition comprising: a thermoplastic resin; and surface-treated cellulose-containing particles obtained by surface-treating cellulose-containing particles with an organic phosphate compound. An average primary particle diameter of the cellulose-containing particles which constitute the surface-treated cellulose-containing particles is 10 to 300 μm and the organic phosphoric acid ester compound contains a C5-12 hydrocarbon group.SELECTED DRAWING: None

Description

The present invention relates to thermoplastic resin compositions, molded articles and electrical and electronic equipment.

Resin compositions are generally used for the interior or exterior of electrical and electronic equipment such as printers and copiers. Such a resin composition generally contains an inorganic filler such as glass fiber from the viewpoint of increasing the strength of the molded product. In recent years, for the purpose of reducing CO ₂ , the use of a resin composition containing a cellulosic material such as a cellulosic fiber instead of an inorganic filler such as glass fiber has been studied.

Cellulose-based fibers have a lighter specific gravity than conventional inorganic fillers such as glass fibers, and are advantageous in reducing CO ₂ . However, since the cellulosic fiber has many polar groups derived from the cellulosic structure, it has a problem that it has a low affinity with a resin showing hydrophobicity and easily aggregates.

To solve such a problem, for example, it has been proposed to surface-treat a cellulosic fiber with a silane coupling agent to suppress the aggregation of the cellulosic fiber (for example, Patent Document 1). However, the aggregation of cellulosic fibers could not be sufficiently suppressed.

Further, the resin composition used for the above-mentioned applications is required to have not only strength but also flame retardancy. Therefore, a flame retardant such as an organic phosphoric acid compound or aluminum hydroxide is further added to the resin composition.

For example, a flame-retardant resin composition (for example, Patent Document 2) containing a polyolefin resin, a cellulose fiber graft-bonded with a phosphorus compound on the surface, and a phosphorus-based flame retardant, a polyolefin resin, and an inorganic flame retardant are supported. A composite resin molded body (for example, Patent Document 3) containing the cellulose particles has been proposed.

Japanese Unexamined Patent Publication No. 2000-239455 JP-A-2018-59065 JP 2001-64451

However, even in the resin compositions of Patent Documents 2 and 3, the affinity between the cellulose fibers or cellulose particles graft-bonded with the phosphorus compound and the resin is low, and the aggregation of the cellulose fibers or cellulose particles cannot be sufficiently suppressed. It was. Therefore, there is a problem that the impact resistance is likely to be lowered due to the aggregation defect, and the strength is likely to vary between the molding shots. There is also a problem that the appearance of the molded product is likely to be deteriorated due to the agglomerates.

Further, since the resin composition containing a large amount of the flame retardant tends to increase the plasticity of the molded product and decrease the strength, it is desired to reduce the content of the flame retardant.

The present invention has been made in view of the above circumstances, and can stably provide a molded product having good flame retardancy and good appearance and strength even if the content of the flame retardant is small. It is an object of the present invention to provide a thermoplastic resin composition, a molded product, and an electric / electronic device.

The present invention relates to the following thermoplastic resin compositions, molded articles and electrical and electronic devices.

The thermoplastic resin composition of the present invention contains a thermoplastic resin and surface-treated cellulose-containing particles obtained by surface-treating cellulose-containing particles with an organic phosphoric acid ester compound, and the average primary particle size of the cellulose-containing particles is , 10-300 μm, and the organic phosphate compound contains a hydrocarbon group having 5 to 12 carbon atoms.

The molded product of the present invention is obtained from the thermoplastic resin composition of the present invention.

The electrical and electronic equipment of the present invention has the molded product of the present invention.

According to the present invention, a thermoplastic resin composition, a molded product and a molded product capable of stably imparting a molded product having good flame retardancy and having good appearance and strength even if the content of the flame retardant is small. Electrical and electronic equipment can be provided.

As described above, in the thermoplastic resin composition containing the cellulose fibers having a relatively large particle size, the cellulose fibers are easily exposed on the surface of the molded product, and the appearance is likely to be deteriorated.

On the other hand, the thermoplastic resin composition containing the cellulose-containing particles having a relatively small particle size is less likely to cause a deterioration in the appearance of the molded product than the thermoplastic resin composition containing the cellulose fibers. However, since cellulose-containing particles having a relatively small particle size tend to agglomerate, the non-uniform presence of agglomerates makes it possible to suppress variations in the strength of the molded body and deterioration of the appearance of the surface of the molded body. There were times when it happened.

In the present invention, surface-treated cellulose-containing particles obtained by surface-treating cellulose-containing particles with an organic phosphoric acid ester compound having a hydrocarbon group having 5 to 12 carbon atoms are used. Since the surface-treated cellulose-containing particles have a hydrocarbon group having an appropriate hydrophobicity on the surface, the surface is appropriately hydrophobicized. Therefore, the surface-treated cellulose-containing particles have a good affinity with the thermoplastic resin exhibiting hydrophobicity and are difficult to aggregate, so that the surface-treated cellulose-containing particles can be highly dispersed in the thermoplastic resin composition. As a result, deterioration of the appearance of the surface of the molded product can be suppressed, and variation in strength between the molded products can be suppressed, and a molded product having stable and good strength can be obtained. Hereinafter, each component constituting the thermoplastic resin composition of the present invention will be described.

1. 1. Thermoplastic Resin Composition The thermoplastic resin composition of the present invention contains a thermoplastic resin and surface-treated cellulose-containing particles.

(Thermoplastic resin)
The thermoplastic resin is not particularly limited, and examples thereof include polyolefin resins such as polyethylene resins and polypropylene resins; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polycarbonate resins, polystyrene resins, and acrylonitrile-butadiene-styrene. A copolymer (ABS resin) is included. The thermoplastic resin may be one kind or a combination of two or more kinds. Of these, polyolefin resins are preferable from the viewpoints of good moldability and low environmental load.

As described above, the polyolefin resin can be a polyethylene-based resin or a polypropylene-based resin.

The polyethylene-based resin may be a homopolymer of ethylene or a copolymer containing ethylene as a main component.

Examples of ethylene homopolymers include low density polyethylene, linear low density polyethylene, linear low density polyethylene, high density polyethylene.

The copolymer containing ethylene as a main component can be, for example, a copolymer of ethylene and an α-olefin. Examples of α-olefins include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene.

The melt flow rate (MFR) of the polyethylene resin at 190 ° C. and a load of 2.16 kg is preferably 0.01 to 200 g / 10 minutes from the viewpoint of obtaining a thermoplastic resin composition having good moldability. More preferably, it is 0.01 to 60 g / 10 minutes.

The polypropylene-based resin may be a homopolymer of propylene or a copolymer containing propylene as a main component.

The copolymer containing propylene as a main component may be, for example, a copolymer of propylene and ethylene, or a copolymer of propylene and other α-olefins. The α-olefin other than propylene can be the same as the above-mentioned α-olefin other than propylene.

The melt flow rate (MFR) of the polypropylene resin at 230 ° C. and a load of 2.16 kg is preferably 0.1 to 200 g / 10 minutes from the viewpoint of obtaining a thermoplastic resin composition having good moldability. From the viewpoint of making it easier to obtain a molded product having further excellent strength, it is more preferably 4 to 30 g / 10 minutes.

Examples of polyolefin resins include polypropylene resins "Prime Polypro", "Polyfine", and "Prime TPO" series manufactured by Prime Polymer Co., Ltd. (for example, Prime Polypro J715M), and polyethylene resin "Hi-Zex" manufactured by Prime Polymer Co., Ltd. , "Neo Zex", "Ult Zex", "More Tech", "Evolu" series (for example, Hi-Zex 1300J) are included.

Among these, polypropylene-based resins are preferable, and propylene homopolymers are more preferable, from the viewpoint of easily increasing the strength and heat resistance of the molded product.

The content of the thermoplastic resin is preferably 50 to 90% by mass with respect to the total amount of the thermoplastic resin and the surface-treated cellulose-containing particles. When the content of the thermoplastic resin is 50% by mass or more, the characteristics of the thermoplastic resin can be sufficiently obtained, and when it is 90% by mass or less, the strength of the molded product can be further increased. From the above viewpoint, the content of the thermoplastic resin is more preferably 60 to 90% by mass with respect to the total amount of the thermoplastic resin and the surface-treated cellulose-containing particles.

(Surface-treated cellulose-containing particles)
The surface-treated cellulose-containing particles are those obtained by surface-treating the cellulose-containing particles with an organic phosphate ester compound. Specifically, a functional group that reacts at least a part of cellulose-derived hydroxyl groups in the cellulose-containing particles with the hydroxyl groups ( For example, it is bonded by reacting with an organic phosphate ester compound having a group represented by X in the formula (1) described later. That is, the surface-treated cellulose-containing particles are surface-modified cellulose-containing particles having a cellulose-containing particle and a group derived from an organic phosphate ester compound bonded to at least a part of hydroxyl groups on the surface thereof.

The cellulose-containing particles used as a raw material are plant-derived fine particles containing cellulose. Specifically, the content ratio of cellulose in the cellulose-containing particles is preferably 30% by mass or more, more preferably 40% by mass or more, and further preferably 50% by mass or more.

The average primary particle size of the cellulose-containing particles is preferably 10 to 300 μm. When the average primary particle diameter of the cellulose-containing particles is 10 μm or more, it is difficult to aggregate, so that deterioration of the appearance of the surface of the molded product due to the aggregates can be suppressed. Further, since the surface area of the particles does not become too large, it is not necessary to increase the treatment amount with the organic phosphoric acid ester compound. When the average primary particle size of the cellulose-containing particles is 300 μm or less, the particle size is not too large, and therefore it is possible to suppress deterioration of the appearance of the surface of the molded body due to the particles being exposed on the surface of the molded body. The average primary particle size of the cellulose-containing particles is more preferably 100 to 200 μm from the viewpoint of further reducing the deterioration of the appearance of the surface of the molded product.

The average primary particle size of the cellulose-containing particles can be measured by microscopic observation. Specifically, the surface or cross section of the molded product of the thermoplastic resin composition is observed with a microscope, the particle size of any 200 cellulose-containing particles is measured, and the average value thereof is defined as the "average particle size". It can be measured by.

Cellulose-containing particles can be obtained, for example, through a step of pulverizing a raw material containing cellulose. Raw materials containing cellulose are not particularly limited, and examples thereof include wood, coconut shells, gramineous plants (rice husks, straw), paper, cotton, and hemp. Among them, wood powder is preferable from the viewpoint that the content ratio of cellulose is high, it is easily available, and the environmental load is small.

The organic phosphoric acid ester compound to be reacted preferably contains a hydrocarbon group having 5 to 12 carbon atoms. When the number of carbon atoms of the hydrocarbon group is 5 or more, the surface of the surface-treated cellulose-containing particles is sufficiently hydrophobic, so that the affinity with the hydrophobic thermoplastic resin can be enhanced. As a result, aggregation of the surface-treated cellulose-containing particles can be suppressed, so that deterioration of the appearance of the surface of the molded product and variation in strength between the molded products can be reduced. When the number of carbon atoms of the hydrocarbon group is 12 or less, insufficient bonding of the organic phosphorus compound to the hydroxyl group on the surface of the cellulose-containing particles due to the long alkyl chain of the organic phosphorus compound (the amount of surface treatment by the organic phosphorus compound). Deficiency) can be suppressed. As a result, the cellulose-containing particles may aggregate in the thermoplastic resin composition, or internal defects may occur due to the variation in the composition, and the variation in the strength between the molded products may be reduced. In addition, since the residue of the unreacted organic phosphorus compound (surface treatment agent) can be suppressed, the aggregation of the residual organic phosphorus compound and the bleed-out to the surface of the molded body can be suppressed, and the strength varies between the molded bodies. Can be reduced. From the above viewpoint, the number of carbon atoms of the hydrocarbon group is more preferably 5 to 10. The number of the hydrocarbon groups may be one or two or more. Examples of such hydrocarbon groups include alkyl groups.

That is, the organic phosphoric acid ester compound is preferably a compound represented by the following formula (1).

In the formula (1), X is a halogen atom or a group represented by the following formula, respectively. Examples of halogen atoms include fluorine atoms, chlorine atoms and bromine atoms, with preference given to chlorine atoms.

R1 is a substituted or unsubstituted alkyl group having 5 to 12 carbon atoms, respectively. The alkyl group may be linear or branched. Examples of substituents that an alkyl group may have include aryl groups such as phenyl groups. When the alkyl group has a substituent, the number of carbon atoms shall include the number of carbon atoms of the substituent.

Examples of substituted or unsubstituted alkyl groups having 5 to 12 carbon atoms include pentyl group (C5), hexyl group (C6), heptyl group (C7), octyl group (C8), nonyl group (C9) and decyl. A group (C10), an undecyl group (C11) and a dodecyl group (C12) are included.

n is 1 or 2, preferably 2.

Examples of the organic phosphate compound represented by the formula (1) include dipentylphosphoyl chloride (C5), dihexylphosphoyl chloride (C6), didecylphosphoryl chloride (C10), and didodecylphosphoryl chloride (C12). ..

As described above, the surface-treated cellulose-containing particles are obtained by reacting the cellulose-containing particles with the organic phosphoric acid ester compound, specifically, the hydroxyl group of the cellulose-containing particles and the compound represented by the formula (1) (organic phosphoric acid ester). It can be obtained by reacting with a group represented by X of compound). The reaction may be carried out in a wet manner or in a dry manner.

In the wet case, 1) the cellulose-containing particles are reacted with the organic phosphate compound in the presence of a basic catalyst such as triethylamine in a solvent such as toluene, and then 2) the obtained reaction product is dried. Therefore, surface-treated cellulose-containing particles can be obtained.

The amount of the organic phosphate compound added when preparing the surface-treated cellulose-containing particles may be set so as to be the surface-treated amount described later, for example, 60 to 300 with respect to the (untreated) cellulose-containing particles. It is preferably by mass, more preferably 90 to 200% by mass.

The above reaction is preferably carried out under heating. The reaction temperature can be, for example, 50-80 ° C.

In the case of the dry type, it can be carried out in the same manner as the above method except that a solvent is not used. The stirring means is not particularly limited, but for example, a mixer for powder stirring can be used. The reaction temperature can be, for example, 20 to 110 ° C.

As described above, the surface-treated cellulose-containing particles are those in which an organic phosphoric acid ester compound is bonded (covalently bonded) to the surface of the cellulose-containing particles. Whether or not the organic phosphate compound is bonded (covalently bonded) to the cellulose-containing particles means that the free phosphorus concentration measured by the following method is below a certain level, specifically, 1% by mass or less, preferably 0. It can be confirmed by the fact that it is 5.5% by mass or less.

Free phosphorus concentration can be measured by X-ray fluorescence analysis as described in EP Bertin's Principles and Practice of Xray Spectrometric Analysis Second Ed. (Plenum Press 1984).
First, the thermoplastic resin composition is extracted with a Soxhlet extractor (solvent: THF) for 5 hours to extract the elution component in the thermoplastic resin composition. Then, the phosphorus concentration in the extracted elution component is measured and converted into the concentration in the thermoplastic resin composition to obtain the "free phosphorus concentration". Generally, an inorganic phosphorus flame retardant or a high molecular weight organic phosphorus is used. Flame retardants cannot be extracted with THF. Therefore, even when the thermoplastic resin composition further contains an inorganic phosphorus flame retardant or a high molecular weight organic phosphorus flame retardant, the free phosphorus concentration can be measured as the phosphorus concentration derived from the surface-treated cellulose-containing particles. ..

Further, the surface-treated cellulose-containing particles preferably have a surface treatment amount of 60 to 300% by mass with respect to the (untreated) cellulose-containing particles. When the surface treatment amount is 60% by mass or more, it is easy to impart sufficient hydrophobicity to the surface of the cellulose-containing particles, and when it is 300% by mass or less, it is easy to suppress a decrease in strength due to an increase in the plasticity of the molded product. .. From the above viewpoint, the amount of the surface treatment with the organic phosphoric acid ester compound is more preferably 90 to 200% by mass with respect to the cellulose-containing particles. The surface treatment amount can be calculated from the following formula.
Surface treatment amount (%) = (mass of surface-treated cellulose-containing particles-mass of untreated cellulose-containing particles) / (mass of untreated cellulose-containing particles) × 100

The content of the surface-treated cellulose-containing particles is preferably 10 to 50% by mass with respect to the total amount of the thermoplastic resin and the surface-treated cellulose-containing particles. When the content of the surface-treated cellulose-containing particles is 10% by mass or more, it is easy to impart sufficient strength to the molded body, and when it is 50% by mass or less, for example, the surface-treated cellulose-containing particles are exposed on the surface of the molded body. It is easy to suppress the deterioration of the appearance due to this. From the above viewpoint, the content of the surface-treated cellulose-containing particles is more preferably 10 to 40% by mass with respect to the total amount of the thermoplastic resin and the surface-treated cellulose-containing particles.

The total amount of the thermoplastic resin and the surface-treated cellulose-containing particles is preferably 70% by mass or more, more preferably 80% by mass or more, and 100% by mass with respect to the thermoplastic resin composition. May be good.

(Other ingredients)
The thermoplastic resin composition of the present invention may further contain components other than the above, as long as the object of the present invention is achieved. Examples of other components include antioxidants, heat stabilizers, UV absorbers, light stabilizers, colorants (pigments and dyes), flame retardants, antistatic agents, foaming agents, drip inhibitors. Above all, the thermoplastic resin composition may further contain a flame retardant from the viewpoint of enhancing flame retardancy.

The flame retardant is not particularly limited, and may be an organic flame retardant or an inorganic flame retardant.

The organic flame retardant is not particularly limited, but may be, for example, an organic flame retardant having a melting point of less than 200 ° C. Examples of such organic flame retardants include organic halogen flame retardants (halogenated bisphenol compounds, halogenated bisphenol-bis (alkyl ether) compounds, etc.), and organophosphorus flame retardants (triphenyl phosphate, etc.). Includes aromatic phosphates, aliphatic phosphates such as trimethyl phosphate, aromatic condensed phosphates, phosphinates, etc.). The organic phosphorus-based flame retardant is different from the organic phosphoric acid ester compound constituting the surface-treated cellulose-containing particles, and is preferably an aromatic phosphoric acid ester or an aromatic condensed phosphoric acid ester.

The inorganic flame retardant is not particularly limited, but for example, red phosphorus, tin oxide, antimony trioxide, antimony hydride, zirconium hydride, barium borate, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, zinc borate, etc. Examples include guanidine nitrogenated and zirconium hydride compounds.

In the present invention, since the surface-treated cellulose-containing particles can exhibit flame retardancy, the amount of the flame retardant added separately can be reduced. Specifically, the content of the flame retardant can be 10% by mass or less with respect to the total amount of the thermoplastic resin and the surface-treated cellulose-containing particles.

2. 2. Method for Producing Thermoplastic Resin Composition The thermoplastic resin composition of the present invention can be produced by any method. For example, the thermoplastic resin composition can be obtained through a step of melt-kneading the thermoplastic resin, the surface-treated cellulose-containing particles, and if necessary, other components. In addition, before the step of melt-kneading, a step of premixing each component in advance may be further carried out.

Examples of means for melt-kneading include Banbury mixers, rolls, single-screw extruders, multi-screw extruders, preferably twin-screw extruders.

Then, the obtained melt-kneaded product is extruded, cooled, granulated or pulverized. For example, it is preferable that the extruded melt-kneaded product is cooled by water cooling or the like and then cut by a pelletizer or the like to be pelletized.

3. 3. Molded product and its use The thermoplastic resin composition of the present invention is usually molded into an arbitrary shape to obtain a molded product. Examples of molding methods include injection molding, extrusion molding, blow molding, vacuum molding, profile extrusion molding, compression molding and gas assist molding.

The shape and dimensions of the molded product are not particularly limited and can be arbitrarily set according to the intended use of the molded product.

The molded body can be used for various purposes such as interior or exterior parts of electrical and electronic equipment (home appliances, OA / media related equipment, optical equipment and communication equipment, etc.), automobiles, mechanical parts, and housing / building parts. .. Above all, from the viewpoint of having excellent strength and good flame retardancy and having a small burden on the environment, it is suitable as an exterior part (particularly a housing) of electrical and electronic equipment such as copiers, printers, personal computers and televisions. Can be used.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.

1. 1. Material of thermoplastic resin composition (1) Thermoplastic resin PE (polyethylene): HI-ZEX (HDPE) 1300J (MFR: 12 g / 10 min, density: 961 kg / m ³ , melting point: 134 ° C.) manufactured by Prime Polymer Co., Ltd.
PP (polypropylene): Prime Polypro J715M manufactured by Prime Polymer Co., Ltd. (MFR: 9 g / 10 min, density: 910 kg / m ³ )

The melt flow rate (MFR), density and melting point of the thermoplastic resin were measured by the following methods.

(MFR)
The measurement was performed in accordance with JIS K 7210 (ISO1133). The measurement temperature was 190 ° C. for PE and 230 ° C. for PP.

(density)
It was measured according to JIS K 7112 (ISO1183).

(Melting point)
The measurement was performed in accordance with JIS K 7121 (ISO11357-3).

(2) Surface-treated cellulose-containing particles <Preparation of surface-treated cellulose-containing particles 1>
To 100 parts by mass of rice husk powder (cellulose content ratio 30% by mass, average primary particle diameter 170 μm) that had been crushed in advance as cellulose-containing particles, 59 parts by mass of triethylamine and 200 parts by mass of toluene were added, and organic while stirring. 120 parts by mass of phosphoric acid ester compound A (dihexyl phosphoryl chloride, C6) was added at 60 ° C. over 60 minutes, and then reacted at 60 ° C. for 2 hours. After neutralizing the triethylamine in the reaction termination solution with an aqueous hydrochloric acid solution, the obtained particles are separated by a filter, washed with water, dried in an oven at 90 ° C. for 24 hours, and 197 parts by mass of surface-treated cellulose. Containing particles 1 were obtained.

<Preparation of surface-treated cellulose-containing particles 2>
To 100 parts by mass of Sugiki powder (cellulose content ratio 50% by mass, average primary particle diameter 200 μm) crushed in advance as cellulose-containing particles, 98 parts by mass of triethylamine and 200 parts by mass of toluene were added, and organic phosphoric acid was stirred while stirring. 120 parts by mass of ester compound A (dihexylphosphoryl chloride, C6) was added at 60 ° C. for 60 minutes, and then reacted at 60 ° C. for 2 hours. After neutralizing triethylamine in this reaction termination solution with an aqueous hydrochloric acid solution, the obtained particles were separated by a filter, washed with water, dried in an oven at 90 ° C. for 24 hours, and contained 202 parts by mass of surface-treated cellulose. Particle 2 was obtained.

<Preparation of surface-treated cellulose-containing particles 3>
To 100 parts by mass of Sugiki powder (cellulose content ratio 50% by mass, average primary particle diameter 200 μm) crushed in advance as cellulose-containing particles, 98 parts by mass of triethylamine and 200 parts by mass of toluene were added, and organic phosphoric acid was stirred while stirring. 120 parts by mass of ester compound B (didecylholyl chloride, C10) was added at 60 ° C. for 60 minutes, and then reacted at 60 ° C. for 2 hours. After neutralizing the triethylamine in the reaction termination solution with an aqueous hydrochloric acid solution, the obtained particles were separated by a filter, washed with water, dried in an oven at 90 ° C. for 24 hours, and contained 204 parts by mass of surface-treated cellulose. Particle 3 was obtained.

<Preparation of surface-treated cellulose-containing particles 4>
To 100 parts by mass of coconut shell powder (cellulose content ratio 25% by mass, average primary particle diameter 180 μm) previously crushed as cellulose-containing particles, 98 parts by mass of triethylamine and 200 parts by mass of toluene were added, and organic phosphorus was stirred while stirring. 120 parts by mass of acid ester compound B (didecylholyl chloride, C10) was added at 60 ° C. for 60 minutes, and then reacted at 60 ° C. for 2 hours. After neutralizing triethylamine in this reaction termination solution with an aqueous hydrochloric acid solution, the obtained particles were separated by a filter, washed with water, dried in an oven at 90 ° C. for 24 hours, and contained 202 parts by mass of surface-treated cellulose. Particle 4 was obtained.

<Preparation of surface-treated cellulose-containing particles 5 to 8>
Surface-treated cellulose-containing particles 5 to 8 were obtained in the same manner as the surface-treated cellulose-containing particles 3 except that the average primary particle diameter of the cellulose-containing particles was changed as shown in Table 1.

<Preparation of surface-treated cellulose-containing particles 9 to 12>
Surface-treated cellulose-containing particles 9 to 12 were obtained in the same manner as the surface-treated cellulose-containing particles 3 except that the type of the organic phosphoric acid ester compound was changed as shown in Table 1.

<Preparation of surface-treated cellulose-containing particles 13>
200 parts by mass of Sugiki powder (cellulose content ratio 50% by mass, average primary particle diameter 200 μm) and 150 parts by mass of triethylamine that had been crushed in advance as cellulose-containing particles were placed in a container and stirred at high speed with a powder stirring mixer. To this was added 240 parts by mass of organophosphate compound B (didecylholyl chloride, C10) over 20 minutes, and the mixture was stirred at 60 ° C. for 1 hour. The obtained particles were placed in an oven and dried at 100 ° C. for 4 hours to obtain 414 parts by mass of surface-treated cellulose-containing particles 13.

The composition of the obtained surface-treated cellulose-containing particles 1 to 13 is shown in Table 1.

<Untreated cellulose-containing particles>
As the untreated cellulose-containing particles, pre-crushed Sugiki powder (cellulose content ratio 50% by mass, average primary particle diameter 200 μm) was used as it was.

<Preparation of electron beam treated cellulose fiber>
As a cellulose fiber, a cotton fiber having an average fiber length of 45 mm was irradiated with an electron beam of 40 kGy (acceleration voltage 250 kV) under a nitrogen atmosphere by an area beam type electron beam irradiator EC250 / 15 / 180L. The obtained fiber was impregnated with a 15% aqueous solution of mono (2-methacryloyloxyethyl) phosphate at room temperature, washed with water, and dried at 150 ° C. for 90 seconds. Next, the obtained fibers were immersed in an aqueous solution of polyallylamine PAA-03 (manufactured by Nitto Boseki Co., Ltd.) for 360 seconds, washed with water and dried to obtain electron beam-treated cellulose fibers.

The average primary particle size of the cellulose-containing particles was measured by the following method.

(Average primary particle size of cellulose-containing particles)
A small amount of the pellet-shaped thermoplastic resin composition described later was sampled and press-molded while heating at a temperature of 300 ° C. to obtain a sheet having a thickness of about 300 μm. The surface of the obtained sheet was magnified and observed with a microscope, the diameters of 200 particles in the field of view were measured, and the average value thereof was taken as the "average primary particle diameter".

(3) Other components APP (organophosphorus flame retardant): PX-200 (manufactured by Daihachi Chemical Industry Co., Ltd., aromatic condensed phosphoric acid ester)

2. 2. Preparation of Thermoplastic Resin Composition <Preparation of Thermoplastic Resin Compositions 1 to 17>
First, the surface-treated cellulose-containing particles, untreated cellulose-containing particles, or electron beam-treated cellulose-containing particles shown in Table 2 or 3 were dried at 80 ° C. for 4 hours using a vacuum dryer. The ingredients shown in Table 2 or 3 were then dry blended.

Next, the mixture obtained by dry blending was supplied at 10 kg / h from the raw material supply port (hopper) of the twin-screw extrusion kneader (KTX-30; Kobe Steel, Ltd.), the temperature of the cylinder was 210 ° C, and the screw was used. The melt kneading was carried out under the condition that the rotation speed of the above was 200 rpm. The molten resin after kneading was cooled in a water tank at 30 ° C. and then pelletized with a pelletizer to obtain thermoplastic resin compositions 1 to 17.

<Evaluation>
The free phosphoric acid concentration, the appearance, strength and flame retardancy of the surface of the molded product of the obtained thermoplastic resin compositions 1 to 17 were evaluated by the following methods.

(Free phosphorus concentration)
The obtained thermoplastic resin composition was extracted with a Soxhlet extractor (solvent: THF) for 5 hours to extract the elution component in the thermoplastic resin composition. Then, the phosphorus concentration of the extracted elution component was measured and used as the "free phosphorus concentration" of the elution component.
The free phosphoric acid concentration is derived from an organic phosphorus compound that is not bonded to the hydroxyl group of the cellulose-containing particles. Therefore, the lower the free phosphoric acid concentration, the less the (unreacted) organic phosphorus compound that is not bonded to the hydroxyl group of the cellulose-containing particles.

(Appearance of the surface)
After drying the obtained pellet-shaped resin composition at 80 ° C. for 4 hours, the cylinder set temperature was set to 230 ° C. and the mold temperature was set to 50 ° C. using an injection molding machine (J55ELII, manufactured by Japan Steel Works, Ltd.). A test piece having a length of 80 mm, a width of 10 mm, and a height of 4.0 mm was obtained.
Next, the surface of the obtained test piece was observed using a shape analysis laser microscope (VK-X100; KEYENCE CORPORATION) and image analysis was performed. Then, the particle size and the dispersed state of the cellulose-containing powder exposed on the surface of the test piece were confirmed. Then, the appearance of the surface was evaluated according to the following criteria.
⊚: Particle size is 250 μm or less and uniformly dispersed ◯: Particle size is more than 250 μm and 1 mm or less, and some agglomerates are observed, but they are almost uniformly dispersed and there is no problem in practical use. : If there are agglomerates with a particle size of more than 1 mm and the dispersion is non-uniform ○ or more, it is judged that there is no practical problem.

(Bending strength)
A test piece similar to the test piece used for evaluating the appearance of the surface was molded using a mold. As for the number of moldings, 300 shots were discarded and then 100 shots were continuously molded. The variation XTS (%) of the tensile strength of the molded product of the obtained resin composition was obtained from the following formula and evaluated according to the following evaluation criteria.
XTS (%) = (TRmax-TRmin) / (TRav) x 100
In the above formula, TRmax represents the maximum value (MPa) of the tensile strength of the resin composition, TRmin represents the minimum value (MPa) of the tensile strength of the resin composition, and TRav represents the tensile strength of the resin composition. Represents the average value of intensity.
⊚: TRav is 1500 MPa or more and XTS is less than 0.5% ◯: TRav is 1500 MPa or more and XTS is 0.5% or more and less than 5% Δ: TRav is 1500 MPa or more and XTS is 5% or more and less than 15% ×: TRav is If it is less than 1500 MPa or XTS is 15% or more, it is judged that there is no practical problem.

(Evaluation 3: Flame retardant)
A test piece was obtained by the same method as the method for producing the test piece used for evaluating the appearance of the surface, except that the test piece was changed to a strip-shaped test piece having a length of 100 mm, a width of 10 mm, and a thickness of 1.6 mm.
Next, the obtained test piece was subjected to humidity control for 48 hours in a thermostatic chamber at a temperature of 23 ° C. and a humidity of 50%, and the UL94 test (plastic material for equipment parts) specified by the US Underwriters Laboratories (UL). The flame retardancy test was conducted in accordance with the combustion test). UL94V is a method for evaluating flame retardancy from the residual flame time and drip property after indirect flame of a burner flame for 10 seconds on a test piece of a predetermined size held vertically. Then, the flame retardancy was evaluated based on the following evaluation criteria.
⊚: 5VA, 5VB, V0 (pass)
◯: V1, V2 (passed)
Δ: HB (failed)
×: Non-standard (failed)
○ If it is above, it is passed.

The evaluation results of the obtained thermoplastic resin compositions 1 to 11 are shown in Table 2; the evaluation results of the thermoplastic resin compositions 12 to 17 are shown in Table 3.

As shown in Table 2, a thermoplastic resin using surface-treated cellulose-containing particles obtained by surface-treating cellulose-containing particles having an average primary particle size within a predetermined range with a predetermined organic phosphate compound. It can be seen that the compositions 1 to 11 have a good appearance on the surface of the molded product and have little variation in strength.

On the other hand, as shown in Table 3, it can be seen that the thermoplastic resin composition 16 using the untreated cellulose-containing particles has a particularly poor appearance on the surface of the molded product and has a large variation in strength.

Further, it can be seen that the thermoplastic resin compositions 12 and 13 using the surface-treated cellulose-containing particles whose average primary particle diameter does not satisfy the predetermined range have a particularly poor appearance on the surface of the molded product. It is considered that if the average primary particle diameter is too small as 5 μm, the surface-treated cellulose-containing particles tend to aggregate; and if 400 μm is too large, unevenness is likely to be formed on the surface of the molded product.

Further, the thermoplastic resin composition 14 using the surface-treated cellulose-containing particles in which the alkyl group of the organic phosphoric acid ester compound has less than 5 carbon atoms has a poor appearance on the surface of the molded product and a large variation in strength. I understand. It is probable that the surface of the surface-treated cellulose-containing particles could not be sufficiently hydrophobic and the affinity with the resin could not be sufficiently enhanced, and the particles were aggregated. Further, the thermoplastic resin composition 15 using the surface-treated cellulose-containing particles in which the alkyl group of the organic phosphoric acid ester compound has more than 12 carbon atoms has a relatively high free phosphorus concentration, and the strength of the molded product varies. You can see that it is big. This is because the long alkyl chain of the organic phosphorus compound (treatment agent) makes it difficult for the hydroxyl group on the surface of the cellulose-containing particles to sufficiently react with the organic phosphorus compound (treatment agent), and the particles aggregate in the resin. It is probable that this was caused by internal defects or the like due to variations in composition.

According to the present invention, a thermoplastic resin composition and a molded product capable of stably imparting a molded product having good flame retardancy even if the content of the flame retardant is small and having good appearance and strength. And electrical and electronic equipment can be provided.

Claims (8)

With thermoplastic resin
Surface-treated cellulose-containing particles obtained by surface-treating cellulose-containing particles with an organic phosphate compound,
Including
The average primary particle size of the cellulose-containing particles is 10 to 300 μm.
The organic phosphate compound contains a hydrocarbon group having 5 to 12 carbon atoms.
Thermoplastic resin composition. The thermoplastic resin is a polyolefin resin.
The thermoplastic resin composition according to claim 1. The cellulose-containing particles are wood flour.
The thermoplastic resin composition according to claim 1 or 2. The organic phosphoric acid ester compound is a compound represented by the following formula (1).
The thermoplastic resin composition according to any one of claims 1 to 3.

(In equation (1),
X is a halogen atom or a group represented by the following formula, respectively.

R1 is a substituted or unsubstituted alkyl group having 5 to 12 carbon atoms, respectively.
n is 1 or 2) The phosphorus concentration of the elution component extracted from the thermoplastic resin composition by Soxhlet using tetrahydrofuran is 1% by mass or less with respect to the thermoplastic resin composition.
The thermoplastic resin composition according to any one of claims 1 to 4. The content of the surface-treated cellulose-containing particles is 10 to 50% by mass with respect to the total amount of the thermoplastic resin and the surface-treated cellulose-containing particles.
The thermoplastic resin composition according to any one of claims 1 to 5. A molded product obtained from the thermoplastic resin composition according to any one of claims 1 to 6. An electrical and electronic device having the molded product according to claim 7.