JP6087263B2 - Manufacturing method of master pellet and wood-like resin molding - Google Patents

Description

  The present invention relates to a resin composition containing wood flour useful as a master pellet, a master pellet made from the resin composition, a woody resin composition containing a master pellet, and a molded product thereof.

For a long time, woody resin moldings in which wood flour is blended with polyolefin or polyvinyl chloride resin (hereinafter also referred to as PVC resin) have been developed as an effective use of wood flour abundantly supplied as a by-product or waste. I came. However, in recent years, from the viewpoint of the strength and rigidity of the molded body, and the influence on the environment, the use of acrylonitrile / butadiene / styrene copolymer resin (hereinafter also referred to as ABS resin) instead of polyolefin and polyvinyl chloride resin has been used. (Patent Document 1, Patent Document 2, and Patent Document 3) have been studied.
Thermoplastic resins such as ABS resin and polyvinyl chloride resin and wood flour have poor affinity in the first place, and uniform dispersion of wood flour in the resin is more difficult as the amount increases. As means to solve this, a method of improving the dispersibility of wood flour using a dispersion aid such as maleic anhydride-modified polyolefin resin, and master resin pellets containing wood flour (hereinafter referred to as master pellets) are manufactured in advance. In addition, there is a method of mixing the master pellet and a thermoplastic resin to obtain a wood powder-containing resin molded body having a predetermined composition.

Even in the latter method, the wood flour must be dispersed and mixed in the master pellet. Furthermore, since it is a master pellet, the content of the wood powder is large, and uniform dispersion of the wood powder and scorching of the wood powder are serious problems.
Conventionally, an additive for paraffin wax or polyolefin wax has been used to solve uniform dispersion and scorching of wood powder (Patent Document 4). Polyolefin wax is solid at room temperature but becomes a low-viscosity liquid at 80 to 120 ° C., and paraffin wax generally has a low melting point.

  The inventors of the present application have studied the preparation of master pellets containing wood flour and ABS resin. When the above paraffin wax or polyolefin wax is used as a dispersion aid, the dispersibility of both is poor, and the obtained master pellets It turned out that the surface smoothness of the film deteriorated and fluttered. If the surface rises up, it may interfere with its handling, such as clogging at the suction port during suction during pneumatic transportation. Furthermore, mixing and melt-molding the master pellet and thermoplastic resin, the mixing and dispersibility when producing a molded product deteriorates. As a result, the processing characteristics of the molded product such as irregularities and cracks on the surface of the molded product, bending It has been found that it also adversely affects mechanical strength such as strength and dimensional stability such as linear expansion.

Japanese Patent Laid-Open No. 11-240961 Japanese Patent Laid-Open No. 2000-7880 JP 2007-39544 A JP 2004-26886 A Japanese Patent No. 4149862

  The inventors of the present application have made extensive studies on the mixing and dispersibility of wood flour and ABS resin, and confirmed that the above problem can be solved when a low stereoregular soft propylene resin is used as an additive. The present invention has been reached.

According to the present invention, (A) 60-100 parts by mass of acrylonitrile / butadiene / styrene copolymer resin, (C) low stereoregular soft propylene polymer 1 to 100 parts by mass of wood flour. A master pellet obtained by melt-molding a resin composition comprising 3 parts by mass is provided.
In the invention of the master pellet ,
1) (D) 1-40 mass parts of inorganic fillers are further contained,
2) It is preferable that the (D) inorganic filler is talc .

Furthermore, with respect to 100 parts by mass of the master pellet, (E) 15 to 80 parts by mass of a thermoplastic resin is mixed to obtain a woody resin composition, and then the woody resin composition is melt-molded. A method for producing a wood-like resin molded body is provided, in particular, E) a thermoplastic resin is (E1) polyvinyl chloride resin, or (E1) polyvinyl chloride resin and (B) acrylonitrile-butadiene-styrene copolymer. The compounding ratio of (A) wood flour, (B) acrylonitrile / butadiene / styrene copolymer resin and (E1) polyvinyl chloride resin in the wood-like resin molded product is 30 to 50% by mass, respectively. , 15 to 45 wt%, 20 to 40 wt% is preferred that a [(a), (B) and (E1) the total amount of the components is 100 wt%].

  The resin composition provided by the present invention is remarkably provided with lubricity due to the presence of a specific additive, and since shear heat generation due to friction with a press roll and a ring die in a pellet mill during pellet production is reduced, The pellet temperature decreases by about 10 to 15 ° C. As a result, not only the thermal deterioration of the master pellet is suppressed, but also a long life of the apparatus such as a press roll and a ring die can be achieved. Similarly, by providing lubricity, the production efficiency of pellets, specifically, the discharge amount of the pellet mill is improved by about 20%.

Furthermore, since the obtained master pellet is prevented from being crushed and the surface becomes smooth, clogging at the suction port during suction by pneumatic transportation is prevented, and a long run is possible. Moreover, since the bulk specific gravity of the pellet itself is improved by about 20%, the filling weight per predetermined storage container increases, leading to a reduction in transportation cost.
Furthermore, when the molded product having a predetermined composition is produced by mixing the master pellet and the thermoplastic resin, the mixed dispersibility is improved, so that the surface roughness and cracking of the obtained molded product are prevented and the processing characteristics are improved. In addition to being excellent, it is also excellent in mechanical strength such as bending strength and dimensional stability such as linear expansion.
Since the obtained master pellet contains an ABS resin as a resin component, a wood powder-containing resin molded article having high rigidity and imparting desired physical properties can be obtained efficiently and with high quality by separately blending with another thermoplastic resin. Can be obtained at

2 is a photograph of a master pellet obtained in Example 1. 2 is a photograph of a master pellet obtained in Comparative Example 1.

The master pellet of the present invention contains (B) 60 to 100 parts by mass of ABS resin and (C) 1 to 3 parts by mass of a low stereoregular soft propylene polymer with respect to (A) 100 parts by mass of wood flour. If necessary, it is obtained by melt-molding a resin composition further comprising (D) 1 to 40 parts by mass of an inorganic filler.
[(A) Wood flour]
As the wood powder, a pulverized product of any wood such as conifer, hardwood or lauan wood is used. The particle size is not particularly limited, but generally a particle size of about 20 to 250 mesh is used. In addition to pulverized wood, crushed materials such as bark, grain husks, and waste wood can also be used. Since the wood powder usually contains 5 to 30% by mass of water, it is preferably 10% by mass or less, particularly preferably 5% by mass or less, generation of bubbles during molding, reduction in mechanical strength, This is suitable from the viewpoint of suppressing appearance defects.

[(B) ABS resin]
The ABS resin used in the present invention is a copolymer of acrylonitrile, butadiene, and styrene, and is a resin excellent in impact resistance, rigidity, tensile strength, and glossiness. Its structure is a heterogeneous structure in which an elastic body such as polybutadiene is dispersed in an island shape in a matrix such as AS (acrylonitrile styrene) resin. To be precise, the three monomers of acrylonitrile, butadiene and styrene are co-polymerized. It is said that it is not a polymer. The content of acrylonitrile is generally 20 to 35%, but there are some that are about 40%. Butadiene is about 5 to 30%. There are also a number of improved ABS resins that replace some of the above three components to improve properties such as gloss, fluidity, and heat resistance. For example, “Techno ABS” (Technopolymer), “UMGABS” (UMGABS) ), “Denka ABS” (Electrochemical Industry Co., Ltd.) and the like are commercially available. In the present invention, these ABS resins can be selected and used according to the purpose.
The blending amount of the ABS resin is 60 to 100 parts by mass with respect to 100 parts by mass of the wood flour. When the amount is less than 60 parts by mass, the amount of resin is insufficient, and the surface on which the wood flour is uniformly dispersed is difficult to form a smooth pellet. If the amount exceeds 100 parts by mass, the amount of resin becomes excessive, and stickiness is generated on the pellet surface, so that mutual adhesion tends to occur, which is not preferable.

[(C) Low stereoregular soft propylene polymer]
In the present invention, a low stereoregular soft propylene polymer (hereinafter also referred to as a soft propylene resin) is a polymer that is polymerized using propylene as a main raw material and a metallocene catalyst that is a homogeneous catalyst. It is a low crystalline and soft propylene polymer having a regular region. Specifically, the intrinsic viscosity [η] obtained by polymerizing propylene and the like at a temperature of about 100 ° C. using a metallocene catalyst composed of a zirconium transition metal complex and an organic boron compound is 0.01 to 1.0, This is a polymer having a regularity fraction ([mm]) of 50 to 90 mol%, a melting point (TmD) of 0 to 120 ° C., and a molecular weight distribution (Mw / Mn) of 4 or less. This is disclosed in detail in (Patent Document 5).
The low stereoregular soft propylene polymer is “El Modu S400” (softening point 93 ° C., weight average molecular weight 45000, molecular weight distribution 2, MFR> 1000 g / 10 min), “El Modu S 600” (softening point 100 ° C., weight average) Molecular weight 70000, molecular weight distribution 2, MFRg / 10min> 300), “El Modu S901” (softening point 120 ° C., weight average molecular weight 120,000, molecular weight distribution 2, MFRg / 10min> 50) etc. are commercially available from Idemitsu Kosan Co., Ltd. Therefore, it is convenient and preferable to use these.
The blending amount of the soft propylene resin is 1 to 3 parts by mass with respect to 100 parts by mass of the wood flour. If the amount is less than 1 part by mass, the effect does not appear, and even if the amount exceeds 3 parts by mass, a dramatic improvement in the effect is not recognized.

[(D) inorganic filler]
The inorganic filler is used to impart rigidity, flame retardancy, mass feeling, etc., for example, calcium carbonate, magnesium carbonate, silica, calcium oxide, titanium oxide, barium sulfate, calcium hydroxide, talc, Examples include mica, aluminum silicate, calcium silicate, carbon black, glass powder, diatomaceous earth, and hydrated gypsum.
These inorganic fillers may be used alone or in combination of two or more. Also, the shape is arbitrarily selected from spherical, plate-like, granule-like, fiber-like and the like. In particular, powder talc having an average particle size of 10 to 30 μm is preferably used in order to improve the dispersibility of the wood powder and to suppress the dimensional change and the linear expansion coefficient upon water absorption.
The compounding quantity of the said inorganic filler is 1-40 mass parts with respect to 100 mass parts of wood flour. When it exceeds 40 parts by mass, the woody feeling is lost, and various physical properties resulting from the resin of the resin molded body are lowered.
In the resin composition for master pellets of the present invention, known additives such as a colorant, a weather resistance agent, an antioxidant, an ultraviolet absorber, and an antistatic agent are added as long as the purpose is not impaired. It can mix | blend according to a well-known formulation.

[Manufacture of master pellets]
The above-mentioned wood powder, ABS resin and essential components of the low stereoregular soft propylene polymer and optional components are mixed before pelletization to obtain a resin composition for molding. The method is not particularly limited, and a known method, for example, a hot blending method using a mixer such as a Henschel mixer is suitably employed.
In hot blending, all the materials to be blended are put into a mixer such as a Henschel mixer, and the temperature is raised to 180 to 200 ° C. at which the ABS resin melts to perform melt dispersion. At this time, since the low stereoregular soft propylene polymer also melts simultaneously in the temperature range, it is possible to uniformly disperse and mix wood powder and inorganic filler.
The obtained resin composition is melted by shearing heat generated by a ring die and a press roll in the apparatus using a pellet manufacturing apparatus such as a pelletizer or a pellet mill, and then compressed (pressed) to a pellet size. Solidify into a cylindrical shape. The columnar solidified product is cut into a predetermined length by a metal blade fixed around the ring die to obtain a columnar pellet. The obtained master pellets are in a high temperature state immediately after being discharged from the pellet mill, so they are cooled to room temperature by a pellet cooler, and after cooling, are pneumatically transported to a storage place (such as a flexible container bag) for use.

[(E) Thermoplastic resin]
The thermoplastic resin mixed with the master pellet is not particularly limited, and a known thermoplastic resin can be used. Specifically, in addition to the ABS resin used for the master pellet, polyolefin resin such as polyethylene and polypropylene (PP); polyamide resin; polyacetal resin; polyester resin such as polyethylene terephthalate and polybutylene terephthalate; fluororesin; polyphenylene sulfide Resin; Styrenic resin such as polystyrene, acrylonitrile-ethylene-styrene resin (AES resin), acrylonitrile-styrene-acrylate (ASA resin); Acrylic resin such as polymethyl methacrylate; Polycarbonate resin; Polyurethane resin; PVC resin; Resin; Commercially available thermoplastic resins such as ethylene-vinyl acetate copolymer resin are listed. Among these thermoplastic resins, ABS resin, ASA resin, PVC resin, or a mixed resin thereof is preferable from the viewpoint of impact resistance, rigidity, and weather resistance.

[(E1) PVC resin]
The PVC resin is not particularly limited as long as it is a resin based on a vinyl chloride homopolymer, and includes a resin whose structure and chemical composition have been partially altered and a resin whose properties have been improved by adding additives. In general, commercially available products can be used as they are. For example, there are a soft polyvinyl chloride resin containing a plasticizer and a hard polyvinyl chloride resin containing no plasticizer. The average degree of polymerization of the resin is usually 700 to 1500 from the viewpoint of ease of extrusion molding and securing of desired physical properties.

Although the kind and compounding quantity of a thermoplastic resin are arbitrarily selected according to the physical property of the target wood-like resin molding, it is 15-80 mass parts normally with respect to 100 mass parts of said master pellets. When the thermoplastic resin is a resin other than ABS resin and is inferior in strength or heat resistance to ABS resin (such as PVC or polyethylene), if the blending amount exceeds 80 parts by mass, ABS in the wood-like resin molded product The resin content decreases, and the strength and heat resistance decrease.
Specifically, in order for the wood-like resin molded body to have self-digestibility without blending a flame retardant, PVC resin alone, or PVC resin and ABS resin, depending on the ABS resin content in the master pellet. The blending ratio of (A) wood flour, (B) ABS resin, and (E1) PVC resin in the woody resin composition is 30 to 50% by mass, 15 to 45% by mass, 20%, respectively. It is preferable to set it to -40 mass% [the total amount of (A), (B) and (E1) component shall be 100 mass%].
Further, in order to make it nonflammable, the mixing ratio of (A) wood flour, (B) ABS resin and (E1) PVC resin in the wood-like resin composition is 40 to 50% by mass, 15 to 30 respectively. It is preferable to set it as the mass% and 30-40 mass% [The total amount of (A), (B) and (E1) component shall be 100 mass%.].

  In the woody resin composition of the present invention, known additives such as colorants, weathering agents, antioxidants, ultraviolet absorbers, antistatic agents and the like are known per se, as long as the purpose is not impaired. Can be blended according to prescription. These additives may be previously contained in the master pellet as described above, or may be blended when preparing the woody resin composition.

[Manufacture of wood-like resin moldings]
The master pellets and the thermoplastic resin are further blended as necessary. The additives are dry blended using a known mixer such as a blender or a Henschel mixer to obtain a woody resin composition.
The obtained wood-like resin composition is made into a wood-like resin molded body having a predetermined shape according to the purpose by various molding methods such as injection molding, vacuum molding, calendar molding, and compression molding. In particular, an extrusion molding method is preferably employed from the viewpoint of productivity and ease of production of a molded body having a complicated cross-sectional shape. The molding machine to be used, molding conditions and the like may be arbitrarily selected and determined from conventionally known ones.

  Since the woody resin molded body of the present invention has a woody appearance, it is a building interior material such as a window frame / door frame or wall material, a structural material such as a furniture edge member or a decorative material, and an exterior of home appliances. It can be widely used for conventional materials that require woody appearance such as wood and housing materials. In particular, if it has self-extinguishing or non-flammability, it has a wooden appearance such as terrace deck material, pipe material, fence material, siding material, balcony material, louver material, etc., and requires flame resistance Useful as a material.

The invention is further described in the examples. The following examples are for illustrative purposes and the invention is not limited in any way. In addition, not all combinations of features described in the embodiments are essential to the solution means of the present invention.
Various components and abbreviations used in the following examples and comparative examples are as follows.
(A) Wood flour A-1: Average particle size 150 μm (50 to 700 μm)
(B) ABS resin B-1: “Clarastic GA-101” (manufactured by Nippon A &L); SP value = 9.8
(C) Low stereoregular soft propylene polymer C-1: “El Modu S400” (manufactured by Idemitsu Kosan Co., Ltd.);
Softening point 93 ° C., molecular weight (Mw) 45000, specific gravity (Kg / m ³ ) 87,
MFR (g / 10min)> 1000, molecular weight distribution (Mw / Mn) 2
C-2: “El Modu S600” (made by Idemitsu Kosan Co., Ltd.);
Softening point 100 ° C., molecular weight (Mw) 70000, specific gravity (Kg / m ³ ) 87,
MFR (g / 10min)> 300, molecular weight distribution (Mw / Mn) 2
(D) Inorganic filler D-1: Talc “SP-40N” (manufactured by Fuji Talc Industry); average particle size 18 μm
(E) Thermoplastic resin E-1: polyvinyl chloride resin “TH1000” (manufactured by Taiyo PVC Co.); polymerization degree 1000, SP value = 9.6
B-1: “Clarastic GA-101” (manufactured by Nippon A &L); SP value = 9.8
(F) Dispersing aid F-1: Polyethylene wax “High Wax 1160H” (Mitsui Chemicals)
F-2: Paraffin wax “LUVAX-1266” (manufactured by Nippon Seiwa)
Evaluation of the master pellets in Examples and Comparative Examples, measurement of bending strength and linear expansion coefficient of the wood-like resin molded body, and evaluation of moldability were performed as follows.
[Evaluation of master pellet]
1) Surface condition of the pellet:
Judgment criteria:
“◎”: Smooth and glossy “◯”: Smooth but poor gloss “×”: Sacreed 2) Wood powder dispersion criteria Criteria:
"◎": No aggregation "O": Less aggregation "X": Many aggregation 3) Workability "Good": Pellets do not adhere to each other, and handling is good "Interaction": Some pellets stick together [Evaluation of molded body]
1) Extrudability of molded product Criteria:
“◎”: The surface of the molded body is smooth “×”: The surface of the molded body has irregularities 2) Measurement and testing method of bending strength of the molded body: Conforms to JIS K7171 • Measuring instrument: AUTOGRAPH AG-50kNG (Shimadzu Corporation) Made)
・ Test environment: Temperature 25 ℃ Humidity 45%
Test piece shape: length 80 mm x width 10 mm x thickness 4 mm (cut out piece)
・ Test speed: 2 mm / min ・ Number of tests: n = 3
3) Measurement of linear expansion coefficient of compact
Test method: Conforms to JIS A1325 method Test environment: Temperature 25 ° C Humidity 45% (24 hours before measurement)
Test piece shape: length 100 mm x width 20 mm x thickness 4 mm (cut out piece)
・ Number of tests: n = 3
The molded body was cut to a length L of 500 mm to prepare a test piece. This test piece was annealed at 70 ° C. for 24 hours and then left in an atmosphere at an arbitrary temperature for 12 hours. Measure. From this measured value, the dimensional change rate of the length L on the basis of the dimension at 0 ° C. was obtained, and the linear expansion coefficient was calculated from this dimensional change rate. In addition, the linear expansion coefficient was calculated | required about three test pieces, and the average value was shown in Table 2.

Example 1
According to the formulation shown in Table 1, (A) wood flour, (B) ABS resin, (C) low stereoregular soft propylene polymer, and (D) inorganic filler were previously mixed in a mixer “FM mixer FM1000” (Japan) Coke Kogyo Co., Ltd.), and this mixture is put into a granulator “Pellet Mill SPM-580” (made by Oike Iron Works), and cylindrical master pellets having a diameter of 4 mm and an aspect ratio of 2 to 2.5 are obtained. Manufactured.
When the surface of the obtained pellet was observed, the surface was smooth and glossy, and there was no aggregation of the wood flour and it was uniformly dispersed. FIG. 1 shows a photograph of the pellet.
The surface temperature immediately after granulation of the pellets granulated from the pellet mill was 170 ° C. The discharge amount of the pellet mill was 450 kg / h (supply amount 470 kg / h). The resulting pellet had a bulk specific gravity of 190 g / 300 ml.
In order to store the obtained pellets, the pellets were sucked by pneumatic transportation and transported to the flexible container bag. As a result, the whole amount (2.6 tons) could be processed without clogging at the suction port. Moreover, the pellets were excellent in handleability without mutual adhesion.

Examples 2-7, Comparative Examples 1-4
A master pellet was prepared according to Example 1 except that the formulation of each component was changed to the blending amounts shown in Table 1. Table 1 shows the results of pellet surface observation and processability.
In Comparative Example 1, the surface temperature immediately after granulation of the pellets was 185 ° C., the discharge amount of the pellet mill was 390 Kg / h (feed amount 470 Kg / h), and the bulk specific gravity of the pellets was 160 g / 300 ml. . In pneumatic transportation to the flexible container bag, 50 times clogging occurred at the suction port before the entire amount was processed. Some pellets were attached to each other. The surface of the obtained master pellet was crispy. The photograph is shown in FIG.

Examples 8 to 10, Comparative Example 5
Using a mixer “FM mixer FM1000” (manufactured by Nihon Coke Kogyo Co., Ltd.) with a prescription shown in Table 2, PVC resin for Example 100 and 100 parts by mass of the master pellets obtained in Example 1 and further ABS resin in Example 10. Next, this mixture was put into a hopper of a single screw extruder and melt kneaded and extruded at a molding temperature of 160 to 200 ° C. to produce a wood-like resin molded body. In Comparative Example 5, the master pellet of Comparative Example 1 in which the low stereoregular soft propylene resin was not blended was used.
The resin molding obtained was evaluated for moldability, bending strength, and linear expansion coefficient. The results are shown in Table 2. In addition, as for the wood-like resin molding obtained in Examples 8-10, as a result of the flame resistance test based on JIS A5721-1995 “plastic deck” (5.6 flame resistance test <JIS K6911 5.24A method>), The flame disappeared within 180 seconds, and the combustion distance was 25 mm or more and 100 mm or less, indicating “self-extinguishing”.

Claims (5)

(A) To 100 parts by mass of wood powder, (B) 60-100 parts by mass of acrylonitrile / butadiene / styrene copolymer resin, (C) 1-3 parts by mass of low stereoregular soft propylene polymer A master pellet obtained by melt molding a resin composition. (D) Furthermore, 1-40 mass parts of inorganic fillers are contained, The master pellet of Claim 1 characterized by the above-mentioned. (D) The master pellet according to claim 2, wherein the inorganic filler is talc. 4. 100 parts by mass of the master pellets according to claims 1 to 3, (E) 15 to 80 parts by mass of a thermoplastic resin are mixed to obtain a woody resin composition, and then the woody resin composition is melt-molded. A method for producing a wood-like resin molded product characterized by comprising: (E) a thermoplastic resin, (E1) is a polyvinyl chloride resin, or (E1) a polyvinyl chloride resin and (B) acrylonitrile-butadiene-styrene copolymer resin, a woody resin molded article, (A The blending ratio of wood powder, (B) acrylonitrile / butadiene / styrene copolymer resin and (E1) polyvinyl chloride resin is 30 to 50% by mass, 15 to 45% by mass, 20 to 40% by mass [( a), (B) and (E1) method for producing a woody resin molded article according to claim 4, characterized in that the total amount of the components a to] 100 mass%.