JP2015189882A - Fiber composite polypropylene-based resin composition for foam molding and manufacturing method of foam molded body using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition suitable for obtaining a polypropylene-based injection foamed body high in foaming ratio, low in surface hardness of a foam molded body and having high touch feel and a manufacturing method of a foam molded body using the same, further the polypropylene-based injection foamed body manufactured by the manufacturing method.SOLUTION: There is provided a fiber reinforced polypropylene-based resin composition for foam molding containing a specific propylene-based resin component polymerized by a metallocene catalyst (a) of 40 to 85 wt.%, a specific elastomer (b) of 15 to 60 wt.% and a specific organic fiber (c) of 5 to 55 pts.wt. based on 100 pts.wt. of total of (a) and (b).

Description

  The present invention relates to a fiber composite polypropylene resin composition for foam molding having a high expansion ratio and a low surface hardness (low hardness) of the foam molded article, a method for producing a molded article using the same, and a foam obtained by the production method. It relates to a molded body.

The field of use of polypropylene resin compositions is expanding as a resin material having excellent physical properties, moldability, recyclability, economy, and the like. In particular, in the fields of automotive parts such as instrument panels and pillars, and electrical equipment parts such as televisions and vacuum cleaners, polypropylene-based resins and composite polypropylene that is reinforced with a filler such as glass fiber and elastomer (rubber) combined with polypropylene-based resins. Polypropylene resin compositions such as resin are excellent in moldability, physical property balance, recyclability and economy, and are therefore widely used in various fields including molded articles.
In these fields, polypropylene-based resin compositions are increasingly being used in polypropylene-based resin compositions to meet the demands for higher quality, larger size, diversified and complicated applications, especially in automotive interior parts. In addition to the moldability and physical property balance of the resin composition and its molded body, improvement in the tactile sensation on the surface of the molded body, mainly soft feeling (low surface hardness) is required.

  For example, it has low shrinkage, good texture transfer, scratch resistance, and good molded appearance, and the surface of the molded product is smooth and soft without foaming. High rigidity, high impact strength, and high A fiber reinforced polypropylene resin composition characterized by containing a specific propylene-ethylene block copolymer obtained using a metallocene catalyst and fibers as a material having heat resistance is disclosed. Although it is described that the composition and its molded article have low shrinkage, soft and smooth tactile feel and high physical property balance, further soft feeling (low hardness) is required depending on applications (for example, Patent Document 1).

  In addition, in the molded product, soft touch can be increased by foaming. For example, as a material having both foamability and flexibility in in-mold foam molding, a mixture containing a specific polypropylene resin, an ethylene copolymer rubber, and a softening agent is dynamically heat-treated in the presence of a crosslinking agent. A thermoplastic elastomer obtained by adding a specific polypropylene resin, a specific propylene / α-olefin copolymer rubber, and a softening agent to the resulting olefinic thermoplastic elastomer, and an ethylene / α-olefin copolymer, A thermoplastic elastomer composition for injection foam molding obtained by mixing with a styrenic thermoplastic elastomer is disclosed (for example, see Patent Document 2). Although it is described that the composition and its foam-molded article have good fluidity and flexibility that is presumed to exhibit a soft tactile sensation, process oil is used as a softening agent. Therefore, it can be easily inferred that the high temperature characteristics deteriorate. Further, since a cross-linking agent is used to improve the melt tension, there is a problem to be improved in that odor remains, and it is difficult to say that a product that is sufficiently satisfactory is provided.

In the foaming of a general polypropylene resin, a normal polypropylene resin is crystalline and has a low melt tension (melting tension), and bubbles are easily broken. As a result, it was difficult to increase the expansion ratio.
Considering the problem of odor and improving the foamability without using a crosslinking aid, specific melt flow rate (hereinafter sometimes abbreviated as MFR) value, die swell ratio, elongational viscosity, first normal A polypropylene-based resin composition for foaming in which a propylene / ethylene block copolymer having a stress difference and a shear stress ratio is blended has been proposed (for example, see Patent Document 3). However, although this method can obtain a foamed molded article having a high foaming ratio and a high rigidity, the surface hardness is not taken into consideration and must be said to be insufficient.

In efforts to foam molded products by combining resin and fiber, for example, a fiber reinforced polyolefin resin composition containing polyolefin resin and organic fiber was used as a foam molded article having excellent appearance and impact strength. A molded body and a molding method are disclosed (for example, see Patent Document 4). The foamed molded product is described as having high impact by containing organic fibers, but the surface hardness and the like of the molded product are not taken into account and are insufficient. I do not get.
Thus, in the conventional examination, for the purpose of obtaining a high expansion ratio, only a method for improving foamability by increasing the melt tension of the resin has been proposed, while on the other hand, the purpose of adding fibers is It is limited only to rigidity and impact properties, and there is no examination or idea of combining a resin and fiber with low melt tension for the purpose of obtaining a high expansion ratio, and further, as an effect, improvement of tactile sensation can also be achieved. No effort has been made.

JP 2013-0676789 A JP 2002-206034 A JP 2012-001655 A JP 2011-189557 A

  The subject of this invention is providing the polypropylene resin composition excellent in the physical property of the product which can be used suitably for various foam molding in view of the present condition of said prior art. Particularly in the field of injection foam molding, a resin composition suitable for obtaining a polypropylene-based injection foam having a high expansion ratio, a low surface hardness of the foam molded body, and a high tactile feel, and a method for producing a foam molded body using the same And a polypropylene-based injection-foamed molded article produced by the production method.

  As a result of intensive studies to solve the above problems, the present inventors have combined organic fibers with a propylene resin having a low melting point, a specific elastomer, and a specific organic fiber to perform foam molding. We have found that by using cell walls, we can achieve a high expansion ratio without having uniform and fine cells, and that we can obtain a polypropylene-based injection-foamed molded product with a low surface hardness as a foamed molded product. It came to do.

That is, according to the first aspect of the present invention, the propylene-based resin component (a) polymerized by the metallocene catalyst (a) 40 to 85% by weight, the elastomer (a) 15 to 60% by weight, (a) and (a ), A fiber reinforced polypropylene resin composition for foam molding, which contains 5 to 55 parts by weight of an organic fiber (U) is provided.
Propylene-based resin component (a): having the requirements specified in the following (a-i) to (a-iv).
(A-i): In the first step, propylene alone or a propylene-ethylene random copolymer component (A-A) having an ethylene content of 7% by weight or less is 30 to 95% by weight; in the second step, the component (a- A propylene-ethylene random copolymer component (A-B) containing 3 to 20% by weight of ethylene more than A) is obtained by sequential polymerization of 70% to 5% by weight (provided that (A-A) And (A-B) is 100% by weight).
(A-ii): Melting peak temperature (Tm) measured by DSC method is 110 ° C to 150 ° C.
(A-iii): In the temperature-loss tangent curve obtained by solid viscoelasticity measurement, the tan δ curve has a single peak at 0 ° C. or lower.
(A-IV): The melt flow rate (MFR: 230 ° C., 2.16 kg load) of the entire propylene resin component (A) is 0.5 g / 10 min to 200 g / 10 min.

Elastomer (A): having the requirements specified in (I-i) below (I-i) Density is 0.86-0.910 g / cm3 and melt flow rate (MFR: 230 ° C., 2.16 kg load) Is 0.5 g / 10 min to 80 g / 10 min.
Organic fiber (c): It has the requirements specified in the following (c).
(Ui): Polyester fiber or polyamide fiber having a melting point of 245 ° C. or higher.

  According to the second invention of the present invention, in the first invention, there is provided a fiber composite polypropylene-based resin composition for foam molding, wherein the organic fiber (c) is an organic fiber to which a polar resin is attached.

According to the third invention of the present invention, a melting step (A) in which a chemical foaming agent (D) is added and melted to the fiber composite polypropylene resin composition for foam molding in the first or second invention, , An injection step (B) for injecting and filling a mold cavity with a fiber composite polypropylene resin composition for foam molding in a molten state or a semi-molten state obtained from the melting step (A), and a foaming step (C) It is a manufacturing method of a fiber composite polypropylene-based resin foam molding, the manufacturing method is a mold opening injection molding method, the melting step (A) satisfies the following conditions (A-i), and the injection step (B) There is provided a method for producing a fiber composite polypropylene resin foam molded article that satisfies the following conditions (Bi) to (B-ii) and the foaming step (C) satisfies the following condition (Ci).
Condition (A-i)
In the melting step (A), 0.005 to 8 parts by weight of the chemical foaming agent (d) is added to 100 parts by weight of the fiber composite polypropylene resin composition for foam molding and melted.
Condition (B-i)
The mold used in the injection step (B) is composed of a fixed mold and a movable mold capable of moving forward and backward, and is smaller than the mold cavity clearance (T1) corresponding to the shape position of the obtained foamed molded body. In the mold cavity clearance (T0), the molten or semi-molten foam composite fiber composite polypropylene resin composition obtained from the melting step (A) is injection-filled into the mold cavity.
Condition (B-ii)
In the injection step (B), the temperature of the fiber composite polypropylene resin composition for foam molding in the molten or semi-molten state obtained from the melting step (A) is [the melting peak temperature (Tm of the polypropylene resin (a)]. )] The above is [the melting point of organic fiber (a) −10 ° C.] or less.
Condition (C-i)
After performing the injection step (B), the mold is retreated to the mold cavity clearance (T1) corresponding to the shape position of the foamed molded product from which the movable mold can be obtained in the foaming step (C), and the mold is expanded by the expansion pressure by the foaming agent. Fill the cavity of the mold cavity.

  According to the fourth invention of the present invention, in the third invention, the mold cavity clearance corresponding to the shape position of the obtained foamed molded product with respect to the mold cavity clearance (T0) in the injection step (B). Provided is a method for producing a fiber composite polypropylene resin foam molded article having a ratio of (T1) (foaming ratio: T1 / T0) in the range of 1.05 to 3.0.

  According to the fifth aspect of the present invention, there is provided a foam molded article obtained by the method for producing a fiber composite polypropylene resin foam molded article according to the third or fourth aspect.

The fiber-reinforced polypropylene resin composition for foam molding of the present invention can achieve a foamed molded product that can achieve a high foaming ratio and has low hardness and high touch.
Therefore, automotive interior parts such as instrument panels, glove boxes, console boxes, door trims, armrests, grip knobs, various trims, pillars, etc., electrical and electronic equipment parts such as vacuum cleaners, various industrial parts, and housing equipment It can be suitably used for applications such as parts.

FIG. 1 is a diagram showing the elution amount and elution amount integration by temperature rising elution fractionation (TREF).

The present invention relates to a fiber reinforced polypropylene resin composition for foam molding, comprising a specific propylene resin component (a) and a specific thermoplastic elastomer (I) and a specific organic fiber (A) in a specific ratio. The present invention relates to a product, a production method using the product, and a foam molded article obtained by the production method.
Hereinafter, the present invention will be described in detail.

1. Propylene resin component (A)
The propylene-based resin component (a) used in the present invention is synthesized by a metallocene catalyst, and further has the requirements specified in the following (a-i) to (a-iv).
(A-i): In the first step, propylene alone or a propylene-ethylene random copolymer component (A-A) having an ethylene content of 7% by weight or less is 30 to 95% by weight; in the second step, the component (a- A propylene-ethylene random copolymer component (A-B) containing 3 to 20% by weight of ethylene more than A) is obtained by sequential polymerization of 70% to 5% by weight (provided that (A-A) And (A-B) is 100% by weight).
(A-ii): Melting peak temperature (Tm) measured by DSC method is 110 ° C to 150 ° C.
(A-iii): In the temperature-loss tangent curve obtained by solid viscoelasticity measurement, the tan δ curve has a single peak at 0 ° C. or lower.
(A-IV): The melt flow rate (MFR: 230 ° C., 2.16 kg load) of the entire propylene resin component (A) is 0.5 g / 10 min to 200 g / 10 min.

(1) Each requirement (a-i): Polymerization method The propylene-based resin component (a) used in the present invention is polymerized using a metallocene catalyst as described above. In the polymerization, in the first step, propylene alone or an ethylene content of 7% by weight or less, preferably 5% by weight or less, more preferably 3% by weight or less of propylene-ethylene random copolymer component (A-A). 30% to 95% by weight of ethylene in the second step, more preferably 3% to 20% by weight of ethylene, preferably 6% to 18% by weight of ethylene, more preferably of component (A). Need to successively polymerize 70% to 5% by weight of a propylene-ethylene random copolymer component (A-B) containing 8% to 16% by weight of ethylene. Here, by setting the difference in ethylene content between the second step component (A-B) and the first step component (A-A) to 3 to 20% by weight, it is possible to obtain a good foam molded article. Become. That is, if the difference in ethylene content between the second step component (A-B) and the first step component (A-A) is less than 3% by weight, the expansion ratio may be lowered. On the other hand, when it exceeds 20% by weight, the compatibility between the component (A-A) and the component (A-B) is lowered, the surface hardness is not sufficiently lowered, and high tactile sensation may not be obtained.
That is, in the propylene-based resin component (a), it is possible to sequentially polymerize different components in the first step and the second step so that the ethylene content is within a predetermined range. The component (A-B) is polymerized after the component (A-A) is polymerized to prevent problems such as adhesion of reaction products to the reactor. It is important to use a method of polymerizing.

  The propylene-based resin component (A) is 30% by weight to 95% of the propylene-ethylene random copolymer component (A-A), with the total amount of (A-A) and (A-B) being 100% by weight. Wt%, preferably 35 to 90 wt%, more preferably 40 to 85 wt%, and propylene-ethylene random copolymer component (A-B) 70 wt% to 5 wt%, preferably 65 to 10 wt% More preferably, it contains 60 to 15% by weight. By setting (A-A) and (A-B) in such a range, the low crystalline component contained in the propylene-based resin component (A) becomes a suitable range, and the fiber composite polypropylene system for foam molding of the present invention. The resin composition (hereinafter, also simply referred to as “resin composition”) can be provided with a characteristic that a high expansion ratio can be achieved.

In addition, the ethylene content of a component (A-A) and a component (A-B) is determined with the following method.
(I) Temperature rising elution fractionation (TREF) and calculation of T (C):
A technique for evaluating the crystallinity distribution of a propylene-based resin component by temperature rising elution fractionation (hereinafter also simply referred to as TREF) is well known to those skilled in the art. The law is shown.
G. Glockner, J. et al. Appl. Polym. Sci. : Appl. Polym. Symp. 45, 1-24 (1990)
L. Wild, Adv. Polym. Sci. 98, 1-47 (1990)
J. et al. B. P. Soares, A .; E. Hamielec, Polymer; 36, 8, 1639-1654 (1995)
The identification of the component (A-A) and the component (A-B) of the present invention is based on TREF.

  A specific method will be described using the figure showing the elution amount and elution amount integration by TREF in FIG. In the TREF elution curve (plot of elution amount against temperature), components (A-A) and (A-B) show their elution peaks at T (A) and T (B), respectively, due to the difference in crystallinity. Is sufficiently large so that separation is possible at an intermediate temperature T (C) (= {T (A) + T (B)} / 2).

The lower limit of the TREF measurement temperature is −15 ° C. in the apparatus used for this measurement, but in the case of the component (A-B) having very low crystallinity or an amorphous component, There is a case where no peak is shown in the measurement temperature range (in this case, the concentration of the component (A-B) dissolved in the solvent is detected at the lower limit of the measurement temperature (ie, −15 ° C.)).
At this time, T (B) is considered to exist below the measurement temperature lower limit, but the value cannot be measured. In such a case, T (B) is the measurement temperature lower limit − It is defined as 15 ° C.
Here, if the integrated amount of the components eluted up to T (C) is defined as W (B) wt%, and the integrated amount of the component eluted at T (C) or higher is defined as W (A) wt%, W (B) Corresponds almost to the amount of the low-crystalline or amorphous component (A-B), and the integrated amount W (A) of the component eluted at T (C) or higher is a component with relatively high crystallinity ( It almost corresponds to the amount of A-A). The elution amount curve obtained by TREF and the above-described methods for calculating the various temperatures and amounts obtained therefrom are performed as illustrated in FIG.

(TREF measurement method)
In the present invention, the TREF is specifically measured as follows. A sample is dissolved in orthodichlorobenzene (ODCB (containing 0.5 mg / mL BHT)) at 140 ° C. to obtain a solution. This is introduced into a 140 ° C. TREF column, cooled to 100 ° C. at a rate of 8 ° C./min, subsequently cooled to −15 ° C. at a rate of 4 ° C./min, and held for 60 minutes. Thereafter, ODCB (containing 0.5 mg / mL BHT) as a solvent is flowed through the column at a flow rate of 1 mL / min, and the components dissolved in ODCB at −15 ° C. are eluted in the TREF column for 10 minutes, and then the temperature is raised. The column is linearly heated to 140 ° C. at a rate of 100 ° C./hour to obtain an elution curve.
The outline of the apparatus used in the present invention is as follows, and it is also possible to determine using an equivalent apparatus or the like.
TREF column: 4.3 mmφ × 150 mm stainless steel column Column filler: 100 μm Surface inactive glass beads Heating method: Aluminum heat block Cooling method: Peltier element (Peltier element is cooled by water)
Temperature distribution: ± 0.5 ° C
Temperature controller: Chino Corporation Digital Program Controller KP1000 (Valve Oven)
Heating method: Air bath oven Measurement temperature: 140 ° C
Temperature distribution: ± 1 ° C
Valve: 6-way valve 4-way valve Injection method: Loop injection method Detector: Fixed wavelength infrared detector MIRAN 1A manufactured by FOXBORO
Detection wavelength: 3.42 μm
High-temperature flow cell: Micro flow cell for LC-IR Optical path length 1.5 mm Window shape 2φ × 4 mm long round Synthetic sapphire window Sample concentration: 5 mg / mL
Sample injection volume: 0.1 mL

(Ii) Separation of component (A-A) and component (A-B):
Based on T (C) determined by the previous TREF, a soluble component (A-B) in T (C) and an insoluble component in T (C) (T-C) by a temperature rising column fractionation method using a preparative fractionator ( A), and the ethylene content of each component is determined by NMR.
As the temperature rising column fractionation method, a detailed measurement method is shown in the following document, for example.
Macromolecules; 21, 314-319 (1988).
Specifically, the following method is used in the present invention.

(Separation conditions)
A cylindrical column having a diameter of 50 mm and a height of 500 mm is packed with a glass bead carrier (80 to 100 mesh) and maintained at 140 ° C.
Next, 200 mL of a sample ODCB solution (10 mg / mL) dissolved at 140 ° C. is introduced into the column. Thereafter, the temperature of the column is cooled to 0 ° C. at a rate of temperature decrease of 10 ° C./hour. After holding at 0 ° C. for 1 hour, the column temperature is heated to T (C) at a heating rate of 10 ° C./hour and held for 1 hour. Note that the temperature control accuracy of the column through a series of operations is ± 1 ° C.
Next, while maintaining the column temperature at T (C), 800 mL of ODCB of T (C) is flowed at a flow rate of 20 mL / min to elute and recover components soluble in T (C) existing in the column. To do.
Next, the column temperature is increased to 140 ° C. at a rate of temperature increase of 10 ° C./min, held at 140 ° C. for 1 hour, and then 800 mL of a 140 ° C. solvent (ODCB) is flowed at a flow rate of 20 mL / min, whereby T (C) Insoluble components are eluted and recovered.
The solution containing the polymer obtained by fractionation is concentrated to 20 mL using an evaporator and then precipitated in 5 times the amount of methanol. The precipitated polymer is recovered by filtration and then dried overnight in a vacuum dryer.

(Iii) Measurement of ethylene content by 13C-NMR:
The ethylene content of each of the component (A-A) and the component (A-B) obtained by the fractionation is determined by analyzing a 13C-NMR spectrum measured by a proton complete decoupling method. As a representative example, the method used in the present invention will be described below.
Model: GSX-400 (carbon nuclear resonance frequency 400 MHz) manufactured by JEOL Ltd.
Solvent: ODCB / heavy benzene = 4/1 (volume ratio)
Concentration: 100 mg / mL
Temperature: 130 ° C
Pulse angle: 90 °
Pulse interval: 15 seconds Integration count: 5,000 times or more The attribution of the spectrum may be performed with reference to the following documents, for example.
Macromolecules; 17, 1950 (1984).
The spectral attributions measured under the above conditions are shown in Table 1. In the table, symbols such as Sαα follow the notation in the following literature, P represents methyl carbon, S represents methylene carbon, and T represents methine carbon.
Carman, Macromolecules; 10,536 (1977)

Hereinafter, when “P” is a propylene unit in a copolymer chain and “E” is an ethylene unit, six types of triads of PPP, PPE, EPE, PEP, PEE, and EEE may exist in the chain. As described in Macromolecules, 15 1150 (1982), the concentration of these triads and the peak intensity of the spectrum are linked by the following relational expressions <1> to <6>.
[PPP] = k × I (Tββ) <1>
[PPE] = k × I (Tβδ) <2>
[EPE] = k × I (Tδδ) <3>
[PEP] = k × I (Sββ) <4>
[PEE] = k × I (Sβδ) <5>
[EEE] = k × [I (Sδδ) / 2 + I (Sγδ) / 4} <6>
Here, [] indicates the fraction of triads, for example, [PPP] is the fraction of PPP triads in all triads.
Therefore, [PPP] + [PPE] + [EPE] + [PEP] + [PEE] + [EEE] = 1 <7>.
Further, k is a constant, I indicates the spectral intensity, and for example, I (Tββ) means the intensity of the 28.7 ppm peak attributed to Tββ.

By using the relational expressions <1> to <7> above, the fraction of each triad is obtained, and the ethylene content is obtained from the following expression.
Ethylene content (mol%) = ([PEP] + [PEE] + [EEE]) × 100
Note that the propylene random copolymer according to the present invention contains a small amount of propylene heterogeneous bonds (2,1-bonds and / or 1,3-bonds), thereby producing the following minute peaks.

In order to obtain an accurate ethylene content, it is necessary to include these peaks derived from heterogeneous bonds in the calculation, but it is difficult to completely separate and identify the peaks derived from heterogeneous bonds. Since the amount is small, the ethylene content in the present invention uses the relational expressions <1> to <7>, as in the analysis of the copolymer produced with a Ziegler-Natta catalyst that does not substantially contain a heterogeneous bond. To ask.
Conversion from mol% to wt% of ethylene content is performed using the following formula.
Ethylene content (% by weight) = (28 × X / 100) / {28 × X / 100 + 42 × (1−X / 100)} × 100
Here, X is the ethylene content in mol%. In addition, the ethylene content [E] W of the entire propylene-ethylene block copolymer is the ethylene content [E] A and [E] B of each of the component (A-A) and the component (A-B) measured from the above. And the weight ratio W (A) and W (B) weight% of each component calculated from TREF, and is calculated by the following formula.
[E] W = {[E] A × W (A) + [E] B × W (B)} / 100 (% by weight)

(A-ii): Melting peak temperature (Tm)
The melting peak temperature (Tm) measured by the DSC (Differential Scanning Calorimetry) method of the propylene resin component (a) used in the present invention is 110 ° C. to 150 ° C., preferably 115 ° C. to 148 ° C., more preferably. It is necessary to be in the range of 120 ° C to 145 ° C. By setting the melting peak temperature (Tm) within such a range, it is possible to obtain a good foamed molded article. That is, when Tm is less than 110 ° C., foam molding of the foam molded article may be difficult. On the other hand, if it exceeds 150 ° C., the expansion ratio may decrease. Tm can be controlled by adjusting the content of ethylene to be copolymerized with the catalyst used or propylene.
The melting peak temperature (Tm) is DSC (Differential Scanning Calorimeter), for example, using DSC6200 model manufactured by Seiko Instruments Inc., taking 5.0 mg of sample, holding at 200 ° C. for 5 minutes, and then 10 ° C. up to 40 ° C. It is a value obtained by crystallization at a temperature lowering speed of / min and further melting and measuring at a temperature rising speed of 10 ° C./min.

(A-iii): Solid Viscoelasticity Measurement In the temperature-loss tangent curve obtained by solid viscoelasticity measurement (DMA), the tan δ curve has a single peak at 0 ° C. or lower.
That is, in the present invention, the component (A-A) and the component (A-B) in the propylene-based resin component (A) are phase-separated in order to express the high tactile sensation of the resin composition and the molded product thereof. If not, but not phase separated, the tan δ curve shows a single peak below 0 ° C.
When the component (A-A) and the component (A-B) are in a phase separation structure, the glass transition temperature of the amorphous part contained in the component (A-A) and the amorphous contained in the component (A-B) Since the glass transition temperatures of the parts are different, the tan δ curve shows a plurality of peaks.

Solid viscoelasticity measurement (DMA) is performed by applying a sinusoidal strain of a specific frequency to a strip-shaped sample piece and detecting the generated stress. Here, the frequency is 1 Hz, and the measurement temperature is raised stepwise from −60 ° C. until the sample is melted and cannot be measured.
Further, it is recommended that the magnitude of the strain is about 0.1% to 0.5%. From the obtained stress, the storage elastic modulus G ′ and the loss elastic modulus G ″ are obtained by a known method, and the loss tangent (= loss elastic modulus / storage elastic modulus) defined by the ratio is plotted against the temperature. The molded product of the propylene-based resin component (a) shows a sharp peak in the temperature range of 0 ° C. or lower, and the peak of the tan δ curve at 0 ° C. or lower generally observes the glass transition of the amorphous part. is there.

Specifically, the solid viscoelasticity measurement (DMA) used in the present invention is as follows, and can also be measured using an equivalent apparatus or the like.
The sample used is a 10 mm width × 18 mm length × 2 mm thickness strip cut out from a 2 mm thick sheet formed by injection molding under the following conditions.
The apparatus uses ARES manufactured by Rheometric Scientific.
Standard number: JIS-7152 (ISO294-1)
Frequency: 1Hz
Measurement temperature: From -60 ° C. until the sample melts.
Strain: Range of 0.1-0.5% Molding machine: TU-15 injection molding machine manufactured by Toyo Machine Metal Co., Ltd. Molding machine set temperature: 80, 80, 160, 200, 200, 200 ° C. from below the hopper
Mold temperature: 40 ℃
Injection speed: 200 mm / sec (speed in the mold cavity)
Injection pressure: 800kgf / cm2
Holding pressure: 800 kgf / cm2
Holding time: 40 seconds
Mold shape: Flat plate (2mm thickness, 30mm width, 90mm length)

(A-IV): Melt flow rate (MFR)
The melt flow rate (MFR: 230 ° C., 2.16 kg load) of the propylene-based resin component (a) used in the present invention is 0.5 g / 10 min to 200 g / 10 min, preferably 1 g / 10 min to 150 g / It is necessary to be in the range of 10 minutes, more preferably 5 g / 10 minutes to 100 g / 10 minutes. By setting the MFR in such a range, it is possible to obtain a good foamed molded product. That is, if the MFR is less than 0.5 g / 10 minutes, the moldability may be significantly reduced. On the other hand, if it exceeds 200 g / 10 minutes, the expansion ratio may be reduced. The MFR can also be adjusted by using a catalyst to be used, an amount of hydrogen used as a chain transfer agent in the polymerization step, and a molecular weight depressant.
The MFR is a value measured according to JIS K7210 at a test temperature = 230 ° C. and a load = 2.16 kg.

(2) Production method (i) Metallocene catalyst The production of the propylene resin component (a) used in the present invention essentially requires the use of a metallocene catalyst.
The type of the metallocene catalyst is not particularly limited as long as the component (a) having the performance of the present invention can be produced, but in order to satisfy the requirements of the present invention, for example, the components as shown below It is preferable to use a metallocene catalyst comprising (a), (b), and component (c) used as necessary.
Component (a): at least one metallocene transition metal compound selected from transition metal compounds represented by the following general formula (1).
Component (b): at least one solid component selected from the following (b-1) to (b-4).
(B-1): A particulate carrier on which an organic aluminum oxy compound is supported.
(B-2): A particulate carrier carrying an ionic compound or Lewis acid capable of reacting with component (a) to convert component (a) into a cation.
(B-3): Solid acid fine particles.
(B-4): Ion exchange layered silicate.
Component (c): an organoaluminum compound.

As the component (a), at least one metallocene transition metal compound selected from transition metal compounds represented by the following general formula (1) can be used.
^{_{Q (C 5 H 4-a}} R 1 a) (C 5 H 4-b R 2 b) MeXY (1)
[Wherein Q represents a divalent binding group that bridges two conjugated five-membered ring ligands, Me represents a metal atom selected from titanium, zirconium, and hafnium, X and Y represent a hydrogen atom, A halogen atom, a hydrocarbon group, an alkoxy group, an amino group, a nitrogen-containing hydrocarbon group, a phosphorus-containing hydrocarbon group or a silicon-containing hydrocarbon group is shown, and X and Y may be the same or different from each other. R ¹ and R ² are hydrogen, hydrocarbon group, halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing hydrocarbon group, boron-containing hydrocarbon group, or phosphorus-containing hydrocarbon group. Indicates. a and b are the number of substituents. ]

  Among them, preferred for the production of the component (a) is a substituted cyclopentadienyl group, a substituted indenyl group, a substituted fluorenyl group crosslinked with a silylene group, a germylene group or an alkylene group having a hydrocarbon substituent as Q. A transition metal compound comprising a ligand having a substituted azulenyl group, particularly preferably a silylene group having a hydrocarbon substituent or a 2,4-position substituted indenyl group bridged by a germylene group, 2,4 Examples thereof include transition metal compounds composed of a ligand having a -position-substituted azulenyl group.

As the component (b), at least one solid component selected from the aforementioned components (b-1) to (b-4) is used. Each of these components is a well-known thing, and can be used selecting it suitably from well-known techniques. Specific examples and manufacturing methods thereof are described in detail in JP-A No. 2002-284808, JP-A No. 2002-53609, JP-A No. 2002-69116, JP-A No. 2003-105015, and the like.
Of the component (b), particularly preferred is the ion-exchange layered silicate of component (b-4), and more preferred are chemical treatments such as acid treatment, alkali treatment, salt treatment, and organic matter treatment. Is an ion-exchange layered silicate.

Examples of the organoaluminum compound used as the component (c) as necessary include the following general formula (2)
AlRaP _3-a (2)
(Wherein R is a hydrocarbon group having 1 to 20 carbon atoms, P is hydrogen, halogen or alkoxy group, a is a number of 0 <a ≦ 3), trimethylaluminum, triethylaluminum, Trialkylaluminum such as tripropylaluminum and triisobutylaluminum or halogen- or alkoxy-containing alkylaluminum such as diethylaluminum monochloride and diethylaluminum monomethoxide. In addition, aluminoxanes such as methylaluminoxane can also be used. Of these, trialkylaluminum is particularly preferred.

  As a method for forming the catalyst, the component (a), the component (b) and, if necessary, the component (c) are brought into contact with each other to form a catalyst. In addition, the contact method will not be specifically limited if it is a method which can form a catalyst, A well-known method can be used.

Moreover, the usage-amount of component (a), (b), and (c) is arbitrary. For example, the amount of component (a) used relative to component (b) is preferably in the range of 0.1 μmol to 1,000 μmol, particularly preferably 0.5 μmol to 500 μmol, relative to 1 g of component (b). The amount of component (c) used relative to component (b) is preferably such that the amount of transition metal is 0.001 μmol to 100 μmol, particularly preferably 0.005 μmol to 50 μmol, relative to 1 g of component (b).
Furthermore, it is preferable that the catalyst used in the present invention is subjected to a prepolymerization treatment in which a small amount of polymer is brought into contact with an olefin in advance.

(Ii) Sequential Polymerization In producing the component (a) used in the present invention, it is necessary to sequentially polymerize the component (a-A) and the component (a-B).
That is, in the present invention, the component (a) is a block copolymer obtained by sequentially polymerizing components having different ethylene contents in the first step and the second step. It is necessary to develop low shrinkage, good grain transfer and scratch resistance, smooth and soft touch without foaming, and high impact strength.
In the present invention, a method of polymerizing the component (A-B) after polymerizing the component (A-A) is used in order to prevent problems such as adhesion of the reaction product to the reactor. It is necessary.
When performing sequential polymerization, either a batch method or a continuous method can be used, but it is generally desirable to use a continuous method from the viewpoint of productivity.

In the case of the batch method, the component (A-A) and the component (A-B) can be polymerized even by using a single reactor by changing the polymerization conditions with time. As long as the effects of the present invention are not impaired, a plurality of reactors may be connected in parallel.
In the case of the continuous method, since it is necessary to polymerize the component (A-A) and the component (A-B) separately, it is necessary to use a production facility in which two or more reactors are connected in series. A plurality of reactors may be connected in series and / or in parallel for each of the component (A-A) and the component (A-B) as long as the effect is not inhibited.

(Iii) Polymerization process For the polymerization process of component (a), any polymerization method such as a slurry method, a bulk method, or a gas phase method can be used. Although it is possible to use supercritical conditions as intermediate conditions between the bulk method and the gas phase method, they are substantially equivalent to the gas phase method, and are therefore included in the gas phase method without particular distinction.
Since component (A-B) is easily soluble in organic solvents such as hydrocarbons and liquefied propylene, it is desirable to use a gas phase method for the production of component (A-B).
For the production of the component (A-A), there is no particular problem in using any process, but when producing the component (A-A) having relatively low crystallinity, the product to the reactor is used. It is desirable to use a vapor phase method in order to avoid problems such as adhesion.
Therefore, it is most desirable to first polymerize the component (A-A) by the bulk method or the gas phase method and then polymerize the component (A-B) by the gas phase method using the continuous method.

(Iv) Other polymerization conditions and the like The polymerization temperature can be used without any particular problem as long as it is within a commonly used temperature range. Specifically, a range of 0 ° C. to 200 ° C., more preferably 40 ° C. to 100 ° C. can be used.
The polymerization pressure varies depending on the process to be selected, but the optimum pressure can be used without any problem as long as it is in a pressure range usually used. Specifically, the relative pressure with respect to atmospheric pressure can be greater than 0 MPa and up to 200 MPa, more preferably in the range of 0.1 MPa to 50 MPa. At this time, an inert gas such as nitrogen may coexist.
When the sequential polymerization of the component (A-A) in the first step and the component (A-B) in the second step is performed, it is desirable to add a polymerization inhibitor into the system in the second step. In the case of producing a propylene-ethylene block copolymer, if a polymerization inhibitor is added to the reactor for carrying out the ethylene-propylene random copolymerization in the second step, the particle properties (fluidity, etc.) of the resulting powder, gel, etc. Product quality can be improved. Various techniques have been studied for this method, and examples thereof include the methods described in Japanese Patent Publication Nos. 63-54296, 7-25960, and 2003-2939. It is desirable to apply the method to the present invention.
In addition, commercially available products corresponding to the propylene-based resin component (a) are widely known (for example, Wellnex series manufactured by Nippon Polypro Co., Ltd.), and products having desired physical properties are purchased and used from these commercially available products. It is also possible.

2. Elastomer (I)
The elastomer (A) used in the present invention satisfies the requirements defined in (I-i) below.
(Ii): The density is 0.86 to 0.910 g / cm3, and the melt flow rate (MFR: 230 ° C., 2.16 kg load) is 0.5 to 80 g / 10 minutes.
The elastomer (A) used in the present invention has important characteristics such as imparting functions such as an expansion ratio improvement and a decrease in surface hardness in the resin composition and the foamed molded article.

  The elastomer (A) used in the present invention represents a thermoplastic elastomer selected from olefin elastomers and styrene elastomers, and it goes without saying that it does not correspond to the propylene resin component (A).

Examples of the olefin elastomer include ethylene / propylene copolymer elastomer (EPR), ethylene / butene copolymer elastomer (EBR), ethylene / hexene copolymer elastomer (EHR), and ethylene / octene copolymer elastomer (EOR). ) And other ethylene / α-olefin copolymer elastomers; ethylene / propylene / ethylidene norbornene copolymers, ethylene / propylene / butadiene copolymers, ethylene / propylene / isoprene copolymers, etc. Examples thereof include an original copolymer elastomer.
Examples of the styrene elastomer include styrene / butadiene / styrene triblock copolymer elastomer (SBS), styrene / isoprene / styrene triblock copolymer elastomer (SIS), styrene-ethylene / butylene copolymer elastomer ( SEB), styrene-ethylene / propylene copolymer elastomer (SEP), styrene-ethylene / butylene-styrene copolymer elastomer (SEBS), styrene-ethylene / butylene-ethylene copolymer elastomer (SEBC), hydrogenated styrene / Butadiene elastomer (HSBR), Styrene-ethylene / propylene-styrene copolymer elastomer (SEPS), Styrene-ethylene / ethylene / propylene-styrene copolymer elastomer (SEEPS) , Styrene - butadiene butylene - styrene copolymer elastomer (SBBS) can be exemplified.
Furthermore, hydrogenated polymer-based elastomers such as ethylene-ethylene / butylene-ethylene copolymer elastomer (CEBC) can also be mentioned.
In particular, when at least one selected from the group consisting of an ethylene / octene copolymer elastomer (EOR), an ethylene / butene copolymer elastomer (EBR) and an ethylene / propylene copolymer elastomer is used, a resin composition and a molded article thereof In addition, it is possible to achieve a good foaming ratio and to obtain a high tactile sensation because the surface of the resulting foamed molded article has a low hardness, and further, it tends to be easily available and economical. From the point of view, it is preferable.
Two or more types of elastomer (a) can be used in combination.

(1) Each requirement (ii) Density and melt flow rate (MFR)
The density of the elastomer (a) used in the present invention is 0.86 to 0.910 g / cm3, preferably 0.865 to 0.908 g / cm3, and more preferably 0.87 to 0.905 g / cm3. It is. By setting the density in such a range, it is possible to obtain a good foamed molded article. That is, if the density is less than 0.86 g / cm 3, the elastomer (I) may become non-uniform in the resin composition and the molded body thereof, and a sufficient expansion ratio may not be obtained. If it exceeds, the hardness may not be sufficiently low and the tactile sensation may be reduced.

  The MFR (230 ° C., 2.16 kg load) of the elastomer (I) used in the present invention is in the range of 0.5 to 80 g / 10 minutes, preferably 1.5 to 50 g / 10 minutes, and more preferably. Is in the range of 2-15 g / 10 min. By setting the MFR in such a range, it is possible to obtain a good foamed molded product. That is, if the MFR is less than 0.5 g / 10 min, the moldability (fluidity) of the resin composition may be reduced, and if it exceeds 80 g / 10 min, a sufficient foaming ratio may not be obtained. is there.

(2) Manufacturing method The elastomer (I) used in the present invention is, for example, an olefin elastomer, an ethylene / α-olefin copolymer elastomer, an ethylene / α-olefin / diene terpolymer elastomer, It is produced by polymerizing each monomer in the presence of a catalyst.
Examples of the catalyst include titanium compounds such as titanium halide, organoaluminum-magnesium complexes such as alkylaluminum-magnesium complexes, so-called Ziegler-type catalysts such as alkylaluminum and alkylaluminum chloride, and WO 91/04257 pamphlet. The metallocene compound catalyst can be used.
As the polymerization method, polymerization can be performed by applying a production process such as a gas phase fluidized bed method, a solution method, or a slurry method. Moreover, the styrene-type elastomer used as an elastomer (a) can be manufactured by the normal anionic polymerization method and its polymer hydrogenation technique.
In addition, since various products of these elastomers are commercially available from many companies, products having desired physical properties can be obtained and used.

(3) Content Ratio The content ratio of the elastomer (a) used in the present invention is 15 to 60% by weight, preferably 17 to 58% by weight, more preferably 20 to 55% by weight (provided that the propylene resin component ( A) and elastomer (A) total 100% by weight). By setting the content of the elastomer (a) in such a range, it becomes possible to obtain a resin composition having good foaming performance. That is, if the content of the elastomer (a) is less than 15% by weight, foamability may be reduced. If the content exceeds 60% by weight, granulation becomes difficult when forming a resin composition, and molding is difficult. Material may not be collected.

3. Organic fiber (U)
The organic fiber (c) used in the present invention satisfies the requirements specified in the following characteristics (ui).
(Ui): Polyester fiber or polyamide fiber having a melting point of 245 ° C. or higher.
The organic fiber (c) used in the present invention has characteristics of imparting functions such as improvement of the expansion ratio and reduction of surface hardness in the resin composition and the foamed molded article.

(1) Each requirement (Ui) Melting point The organic fiber (U) used in the present invention is a polyester fiber or a polyamide fiber, and its melting point is 245 ° C or higher, preferably 250 ° C or higher. When the melting point is not observed in the organic fiber (c), the softening point only needs to indicate the same temperature, and the same effect can be obtained. When the melting point of the organic fiber (U) exhibits such a temperature, it is possible to achieve a good foaming ratio. That is, when the melting point of the organic fiber (U) is less than 245 ° C., the fiber melts during foam molding, and the expansion ratio may be reduced.

  Polyester fiber or polyamide fiber can be used without any particular limitation. From the viewpoint of handling / workability and mechanical properties, PET (polyethylene terephthalate) fiber (melting point 260 ° C., glass transition temperature 67 ° C.), PEN (polyethylene naphthalate) ) Fiber (melting point 272 ° C., glass transition temperature 113 ° C.) is preferred. The manufacturing method of the organic fiber is not particularly limited, and is manufactured by various known manufacturing methods. Two or more organic fibers can be used in combination.

  If the fiber diameter of the organic fiber (c) is too large, the surface unevenness of the molded part becomes conspicuous and a suitable molded appearance cannot be obtained. On the other hand, if it is too thin, it is easy to melt during molding, easily cut, and the material cost becomes very high. From these circumstances, the single yarn fineness of the organic fiber is preferably about 1 to 20 dtex, particularly about 2 to 15 dtex. The fiber diameter is obtained by cutting the fiber perpendicular to the fiber length direction, measuring the diameter by observing the cross section under a microscope, and calculating the average value of the diameters of 100 or more fibers.

If the length of the organic fiber (c) is too short in the molded part, the expansion ratio will not increase. On the other hand, when too long, fluidity | liquidity will fall and foamability will fall. From these circumstances, the length of the organic fibers is preferably 4 to 20 mm, particularly 5 to 15 mm in terms of average fiber length in the component molded body.
In the present specification, the fiber length represents a length in the case of using ordinary roving-like or strand-like fibers as organic materials before being melt-kneaded. However, in the case of an organic fiber-containing pellet obtained by melt-extrusion processing to be described later and integrating a large number of continuous organic fibers, the length of one side (extrusion direction) of the pellet is the same as the length of the fiber in the pellet. Therefore, the length of one side (extrusion direction) of the pellet is defined as the fiber length.
In addition, in this specification, fiber length is calculated | required by measuring with a microscope and calculating the average value of the length of 100 or more fibers.
Specifically, for example, after diffusing organic fibers on a thin glass plate, the length of 100 or more fibers is measured using a digital microscope (for example, VHX-900 manufactured by Keyence Corporation), and the average value is calculated. Depends on how you do it.

These organic fibers can be used as “organic fiber-containing pellets” by integrating and integrating an arbitrary amount of, for example, a propylene-based resin component (A) and the like and a large number of continuous organic fibers by melt extrusion.
In the case of such an organic fiber-containing pellet, as described above, the fiber length is the length of the organic fiber-containing pellet (extrusion direction), and preferably 4 to 20 mm.
The method for producing such an organic fiber-containing pellet is not particularly limited, and a known method represented by a so-called pultrusion method can be used.

In the organic fiber-containing pellet, the organic fiber content is preferably 20% by weight to 70% by weight based on 100% by weight of the whole pellet.
When organic fiber-containing pellets having an organic fiber content of less than 20% by weight are used in the present invention, foamability may be reduced. On the other hand, when an amount exceeding 70% by weight is used, the appearance and There is a risk of reducing moldability (fluidity).

(2) Content Ratio The content ratio of the organic fiber (c) used in the present invention is 5 to 55 parts by weight, preferably 8 to 50 parts by weight with respect to 100 parts by weight as a total of the propylene resin component (a) and the elastomer (a). Parts, more preferably 10 to 45 parts by weight. By setting the content of the organic fiber (u) in such a range, the resin composition has good foaming performance. That is, when the content ratio of the organic fiber (c) is less than 5 parts by weight, the foaming part may be sufficiently strengthened by the organic fiber (c) and the foamability may be lowered. On the other hand, when it exceeds 55 parts by weight, the fluidity is lowered and the moldability and foamability tend to be lowered.

4). Polar resin The organic fiber (c) can have a polar resin attached to its surface. Here, polar refers to the characteristics of a more polar compound than a non-polar propylene resin.

  Examples of polar resins attached to organic fibers (U) include unsaturated polyesters, vinyl ester resins, epoxy resins, phenol (resole type) resins, urea / melamine resins, polyimides, urethane resins, copolymers of these, and modifications. And thermosetting resins such as body. Moreover, thermoplastic resins, such as saturated polyester, polyamide, acrylic resin, these copolymers, and a modified body, are also mentioned. As the polar resin, an epoxy resin or a urethane resin, which is a thermosetting resin, is particularly preferable from the viewpoint of handling / workability and mechanical properties. More preferably, it is an epoxy resin.

  Specific examples of the epoxy resins (including epoxy compounds) include diglycidyl ether compounds such as ethylene glycol diglycidyl ether and polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether, 1, 4 -Butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, polyalkylene glycol diglycidyl ethers and the like. Polyglycidyl ether compounds include glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ethers, sorbitol polyglycidyl ethers, arabitol polyglycidyl ethers, trimethylolpropane polyglycidyl ethers, pentaerythritol poly Examples thereof include glycidyl ethers and polyglycidyl ethers of aliphatic polyhydric alcohols. Preferably, it is an aliphatic polyglycidyl ether compound having a highly reactive glycidyl group. More preferably, polyethylene glycol diglycidyl ethers, polypropylene glycol diglycidyl ethers, alkanediol diglycidyl ethers and the like are preferable.

  In addition, as a polar resin made to adhere to the said propylene-type resin component (a) and organic fiber (c), the modified body of an olefin resin, for example, the acid-modified olefin resin modified with maleic anhydride etc. is remove | excluded. If an olefin resin modified with a compound having such a polar group is used, the interfacial strength between the propylene resin as a matrix resin and the fiber increases, and sufficient foaming performance may not be obtained. is there.

5. Foaming agent The foaming agent used in the fiber composite polypropylene resin composition for foam molding of the present invention is not particularly limited, and chemical foaming agents (d), physical foaming agents, microcapsules, and the like can be used. Among them, it is desirable to use the chemical foaming agent (D) from the viewpoints of ease of handling and cost, and stable and good injection-foamed molded articles (surface tension, expansion ratio, appearance).

(1) Types, functions, etc. Examples of the types of foaming agents include chemical foaming agents (d), physical foaming agents, and microcapsules. These foaming agents can be used alone or in admixture of two or more.
Examples of the chemical blowing agent (d) include inorganic chemical blowing agents such as sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, and ammonium nitrite, azodicarbonamide (ADCA), N, N′-dinitroso. Examples thereof include organic chemical foaming agents such as pentamethylenetetramine, benzenesulfonyl hydrazide, and 4,4′-diphenyldisulfonyl azide.

  For these chemical foaming agents (d), an organic acid such as citric acid that promotes the generation of gas as an additive, if necessary, in order to stably and uniformly make the foamed foam cells, An organic acid metal salt such as sodium citrate can be used and added together, or a nucleating agent such as inorganic fine particles such as talc and lithium carbonate can be added.

  As the chemical foaming agent (d), an inorganic type is preferable from the viewpoint that a normal injection molding machine can be used safely and uniform bubbles are easily obtained in the molded product. As described above, the chemical foaming agent (d) includes various inorganic and organic types, and preferred chemical foaming agents (d) and additives include sodium bicarbonate, citric acid, sodium citrate, And a mixture of two or more of these, and particularly preferred are sodium bicarbonate, a combination of sodium bicarbonate and sodium citrate, and a combination of sodium bicarbonate and citric acid.

  In addition, the chemical foaming agent (d) may be used after granulating as a masterbatch based on a polyolefin resin from the viewpoints of handleability, storage stability, and dispersibility in polypropylene resin. it can. Thereby, contamination of the hopper of the molding machine and adhesion of powder to the surface of the molded body can be suppressed. In this case, it is preferably used as a master batch of polyolefin resin having a concentration of 10 to 50% by weight.

Examples of the physical foaming agent include inert gas, low-boiling organic solvent vapor, halogen-based inert solvent vapor, and air.
Examples of the inert gas include carbon dioxide, nitrogen, argon, helium, neon, and astatine. Examples of the low boiling point organic solvent vapor include methanol, ethanol, propane, butane, and pentane. Examples of the halogen-based inert solvent vapor include dichloromethane, chloroform, carbon tetrachloride, chlorofluorocarbon, and nitrogen trifluoride. Among these, it is preferable to use an inert gas because it is not necessary to use steam, is inexpensive, and has a very low risk of environmental pollution and fire. Among them, carbon dioxide, nitrogen, argon, and helium are preferable. In particular, carbon dioxide and nitrogen are preferable.
Furthermore, the physical foaming agent is preferably in a supercritical state, which has the advantage of facilitating gas melting into the resin.
A physical foaming agent is injected into a cylinder of an injection molding machine as a gaseous or supercritical fluid, dispersed or dissolved, and functions as a foaming agent by being pressure-released after being injected into a mold. Is.

Microcapsules are obtained by encapsulating a foaming agent (expansion agent) in a shell made of various thermoplastic resins. Examples of the blowing agent (swelling agent) include specific freons such as trichlorofluoromethane, dichlorofluoromethane, and dichlorofluoroethane, alternative freons, hydrocarbons such as n-pentane, isopentane, isobutane, and petroleum ether, Examples thereof include chlorinated hydrocarbons such as methyl chloride, methylene chloride, and dichloroethylene. The average particle size of the microcapsule foaming agent is usually 2 to 50 μm.
These microcapsules are usually supplied to an injection molding machine or the like after being previously mixed with the component A or the like.

(2) Blending Ratio The blending ratio of the foaming agent in the fiber composite polypropylene resin composition for foam molding of the present invention may be appropriately set in view of the type of foaming agent, the foaming ratio, the injection foam molding conditions, and the like. For example, when a chemical foaming agent (d) is used, 0.005 to 8 parts by weight is preferable per 100 parts by weight of the fiber composite polypropylene resin composition, more preferably 0.01 to 8 parts by weight, and still more preferably 0. .1 to 5 parts by weight.
The blending ratio in this case is a substantial concentration of the foaming agent. For example, when a masterbatch of the foaming agent and the polyolefin resin is used, the blending ratio is calculated based on the concentration of the foaming agent contained in the masterbatch. When the blending ratio of the foaming component is less than 0.005 parts by weight, the foam composite fiber composite polypropylene resin composition does not sufficiently foam, while when the blending ratio exceeds 8 parts by weight, the foam molding fiber composite The surface appearance of the polypropylene resin composition and the foamed molded product is remarkably impaired, or secondary foaming phenomenon (a phenomenon in which the surface of the injection foamed molded product swells in a blistering state due to excessive remaining foaming gas) is caused. Also disadvantageous.
Moreover, when using a physical foaming agent, it sets suitably by adjusting the injection pressure of the gas to be used, for example. If the gas injection pressure is insufficient or excessive, as in the case of the chemical foaming agent, the fiber composite polypropylene resin composition does not sufficiently foam, or the surface appearance of the injection foamed molded article deteriorates. To do.

6). Optional additive component The resin composition of the present invention contains various optional additive components such as a modified polyolefin, a molecular weight depressant, a lubricant, and an antioxidant, as long as the effects of the present invention are not significantly impaired. Can do.
The optional additive component may be used in combination of two or more, may be added to the resin composition, each component of the above (a) to (e) such as the propylene resin component (a) and its master batch. May be added in advance, and two or more of these components may be used in combination. In the present invention, the content of the optional additive component is not particularly limited, but is usually about 0.01 to 0.5 part by weight in 100 parts by weight of the resin composition, and is appropriately selected according to the purpose.

(1) Molecular weight depressant The molecular weight depressant is effective for imparting and improving moldability (fluidity).
As the molecular weight depressant, for example, various organic peroxides and so-called decomposition (oxidation) accelerators can be used, and organic peroxides are preferable.
Examples of the organic peroxide include benzoyl peroxide, t-butyl perbenzoate, t-butyl peracetate, t-butyl peroxyisopropyl carbonate, 2,5-di-methyl-2,5-di- (benzoylperoxide). Oxy) hexane, 2,5-di-methyl-2,5-di- (benzoylperoxy) hexyne-3, t-butyl-di-peradipate, t-butylperoxy-3,5,5-trimethylhexa Noate, methyl-ethylketone peroxide, cyclohexanone peroxide, di-t-butyl peroxide, dicumyl peroxide, 2,5-di-methyl-2,5-di- (t-butylperoxy) hexane 2,5-di-methyl-2,5-di- (t-butylperoxy) hexyne-3,1,3-bis- (t-butyl Luperoxyisopropyl) benzene, t-butylcumyl peroxide, 1,1-bis- (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis- (t-butylperoxy) Cyclohexane, 2,2-bis-t-butylperoxybutane, p-menthane hydroperoxide, di-isopropylbenzene hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide, p-cymene hydroperoxide, 1 , 1,3,3-tetra-methylbutyl hydroperoxide and 2,5-di-methyl-2,5-di- (hydroperoxy) hexane selected from the group consisting of one or more Can be mentioned.

(2) Lubricant Lubricant is effective for imparting and improving the releasability during molding of the resin composition and its molded body. Examples of the lubricant include fatty acid amides such as oleic acid amide, stearic acid amide, erucic acid amide, and behenic acid amide, butyl stearate, and silicone oil.

(3) Antioxidant Antioxidant is effective in preventing deterioration of the quality of the resin composition and its molded product. Examples of the antioxidant include a phenol-based, phosphorus-based and sulfur-based antioxidant.

(4) Others Further, the resin composition of the present invention is a polyolefin resin other than the propylene resin component (a), a thermoplastic resin such as a polyamide resin or a polyester resin, and an elastomer within a range that does not significantly impair the effects of the present invention. An elastomer (rubber component) other than (a) can be contained.
As these optional components, various products are commercially available from many companies, and desired products can be obtained and used according to the purpose.

7). Manufacturing method of foam composite fiber composite polypropylene resin composition Pellet as a molding raw material comprising a resin composition containing organic fibers (U) is dispersed so that the organic fibers (U) are randomly entangled in the matrix. Compound pellets may be used, or fiber uniaxially oriented pellets obtained by a pultrusion method called a pultrusion method that is generally put to practical use with glass fiber reinforced thermoplastic resins or the like. Moreover, the blend pellet of a high concentration fiber masterbatch pellet and the pellet for dilution may be sufficient. It is preferable to produce the blended pellets because advantages such as suppression of an increase in the types of pellet grades, cost reduction by mass production of a single material, and prompt customer service can be obtained.

  When producing pellets containing organic fibers (U), it is preferable that the organic fibers (U) are combined with the propylene resin component (A) so that the organic fibers (U) are not melt plasticized, and the organic fibers (U) are supplied. The lower limit of the processing temperature of the part to be applied is preferably 160 ° C. or higher. The upper limit is when the melting point (softening point for those having no melting point) of the organic fiber (U) is 320 ° C. or lower, 20 ° C. or lower, when the melting point is 320 ° C. or higher, and the organic fiber (U) is heated. Even if it does not melt plasticize, it is preferably 300 ° C. or lower. When any organic fiber (U) is selected, if the processing temperature exceeds 300 ° C., the olefin-based resin component (A) is significantly decomposed by heat and may ignite or ignite.

8). Production Method and Properties of Foam Molded Body The foam molding method for producing the foam molded body in the present invention is not particularly limited, and usually includes a foam molding method using an injection molding machine or an injection compression molding machine.
As a foam molding method, for example, in a mold cavity, a fiber composite polypropylene-based resin composition for foam molding is injection-filled while retreating the movable mold at a pressure equal to or higher than the foaming pressure to form a skin layer. An example is a method in which the core layer is foamed by further retracting the movable mold after filling is completed.

  The method for producing a foam molded article preferably used in the present invention includes a melting step (A) in which a chemical foaming agent (d) is added to the above-mentioned fiber composite polypropylene resin composition for foam molding, and the melting A production method comprising an injection step (B) for injection-filling a mold cavity with a fiber composite polypropylene resin composition for foam molding in a molten state or a semi-molten state obtained from step (A), and a foaming step (C). The manufacturing method is a mold opening injection foaming method, the melting step (A) satisfies the following conditions (A-i), and the injection step (B) is performed under the following conditions (Bi) to (B- It is a method for producing a fiber composite polypropylene-based resin foam molded article that satisfies ii) and the foaming step (C) satisfies the following condition (Ci).

Condition (A-i)
In the melting step (A), 0.005 to 8 parts by weight of the chemical foaming agent (d) is added to 100 parts by weight of the fiber composite polypropylene resin composition for foam molding and melted.

Condition (B-i)
The mold used in the injection step (B) is composed of a fixed mold and a movable mold capable of moving forward and backward, and is smaller than the mold cavity clearance (T1) corresponding to the shape position of the obtained foamed molded body. In the mold cavity clearance (T0), the molten or semi-molten foam composite fiber composite polypropylene resin composition obtained from the melting step (A) is injection-filled into the mold cavity.
Condition (B-ii)
In the injection step (B), the temperature of the foam composite fiber composite polypropylene resin composition for foam molding obtained from the melting step (A) is [melting peak temperature of propylene resin component (a) ( Tm)] or more and [melting point of organic fiber (U) −10 ° C.] or less.

Condition (C-i)
After performing the injection step (B), the mold is retreated to the mold cavity clearance (T1) corresponding to the shape position of the foamed molded product from which the movable mold can be obtained in the foaming step (C), and the mold is expanded by the expansion pressure by the foaming agent. Fill the cavity of the mold cavity.

  As a method for producing an injection foam molding using an injection molding machine, a short shot foam molding method and a mold opening injection foam molding method (core back method, moving cavity method, mold cavity expansion foam molding method) are known. . In particular, the mold-opening injection foaming method has a uniform surface quality on the surface of the resulting foamed molded product, excellent product dimensional accuracy such as uneven thickness, and production stability during mass production. In particular, it is advantageous for manufacturing automobile interior parts and the like that require such characteristics. However, conventionally, when foaming is performed using a normal propylene-based resin, bubbles are broken, so that there is a problem that cells by the foamed gas are not sufficiently formed. In the production method preferably used in the present invention, the above-described foam-molded fiber composite polypropylene resin composition was successfully subjected to the following steps to eliminate these problems.

The manufacturing method of the fiber composite polypropylene resin foam molded article of the present invention includes a melting step (A), an injection step (B), and a foaming step (C). Hereinafter, each of these steps will be described in order.
(1) Condition (Ai)
The melting step (A) satisfies the following condition (A-i).
Condition (A-i)
In the melting step (A), 0.005 to 8 parts by weight of the chemical foaming agent (d) is added to 100 parts by weight of the fiber composite polypropylene resin composition for foam molding and melted.
A more preferable blending amount of the chemical foaming agent (d) with respect to 100 parts by weight of the fiber composite polypropylene resin composition for foam molding is 0.01 to 5 parts by weight. By setting the blending amount of the chemical foaming agent (d) in such a range, it is possible to achieve foaming sufficient to achieve the desired foaming ratio, and the effect of reducing surface appearance defects due to gas can be obtained. Is as described above. That is, if the blending amount is less than 0.005 parts by weight, the foam composite fiber composite polypropylene resin composition may not sufficiently foam, whereas if the blending ratio exceeds 8 parts by weight, the foam molding fibers A secondary foaming phenomenon of the composite polypropylene resin composition and the injection foamed molded product (a phenomenon in which the surface of the injection foamed molded product swells in a blistering state due to excessive remaining foaming gas) may occur. Also, compared to polypropylene resins, chemical foaming agents generally require many steps for synthesis and are produced in a small amount, so the cost is higher than the main polypropylene resin and the amount added is too large. This is also an economic disadvantage. The chemical foaming agent (D) is as described above.

(2) Condition (Bi)
The injection step (B) satisfies the following condition (Bi).
Condition (B-i)
The mold used in the injection step (B) is composed of a fixed mold and a movable mold capable of moving forward and backward, and is smaller than the mold cavity clearance (T1) corresponding to the shape position of the obtained foamed molded body. In the mold cavity clearance (T0), the molten or semi-molten foam composite fiber composite polypropylene resin composition obtained from the melting step (A) is injection-filled into the mold cavity.
The mold used in the injection process (B) is composed of a fixed mold and a movable mold that can be moved forward and backward. This fixed mold is fixed to a fixed die plate of an injection molding machine, and a molten resin is used. It has a runner part that is fed from the tip of the injection cylinder. The runner is connected to the gate at the cavity entrance. Depending on the product shape, it has gate and cavity shapes. The movable mold is fixed to the moving die plate of the injection molding machine. Therefore, it moves simultaneously with the die plate. Depending on the product shape, it has gate and cavity shapes.

  The initial thickness T0 is usually 1.0 mm to 5.0 mm, preferably 1.0 to 3.0 mm. Further, the expansion ratio: T1 / T0 is preferably 1.05 to 3.0, and more preferably 1.5 to 3.0. By setting the initial thickness T0 within such a range, for example, a large product such as a door trim of an automobile interior part can be filled by injection, and a sufficiently foamed molded body having a low hardness can be obtained. . That is, if T1 / T0 is less than 1.05, low surface hardness may not be obtained. Moreover, in order to exceed 3.0, many foaming agent additions are needed, and there exists a possibility that the surface external appearance may be impaired remarkably and the thickness of a foaming molded product may become non-uniform | heterogenous.

  In the production method of the present invention, in the mold cavity clearance (T0), the molten or semi-molten foam composite fiber composite polypropylene resin composition obtained from the melting step (A) is injected and filled into the mold cavity. To do. Here, the molten state means that the polypropylene resin is melted and the organic fiber (c) contained therein is partly melted and dispersed from the shear heat generation in the step (A), and the semi-molten state is a polypropylene type. It means that the resin is melted and the organic fiber (U) contained therein is not melted but is softened compared to normal temperature. Here, if the filling time at the time of injection filling is long, there is a concern about the adverse effect of insufficient foaming in the foaming step (C) due to cooling and solidification of the filled fiber composite polypropylene resin composition for foam molding. It is hoped that it is short. The injection filling time is influenced by the size of the product, the capacity of the molding machine, molding conditions, etc., but the injection filling time for general automobile interior parts is usually within 10.0 seconds, preferably within 6.0 seconds. is there. By setting the injection filling time in such a range, an effect that uniform foamability is obtained in the entire product can be obtained.

(3) Condition (B-ii)
The injection step (B) satisfies the following condition (B-ii).
Condition (B-ii)
In the injection step (B), the temperature of the molten or semi-molten foam-molded fiber composite polypropylene resin composition obtained from the melting step (A) is the melting peak temperature (Tm) of the propylene resin component (a). ) The melting point of the organic fiber (U) is −10 ° C. or lower.

  In the injection step (B), the temperature of the molten or semi-molten foam-molded fiber composite polypropylene resin composition obtained from the melting step (A) is the melting peak temperature (Tm) of the propylene resin component (a). ) The melting point of the organic fiber (U) is −10 ° C. or lower, preferably the melting peak temperature (Tm) of the propylene resin component (A) + 10 ° C. or higher, the melting point of the organic fiber (U) is −15 ° C. or lower, and Preferably, the melting peak temperature (Tm) of the propylene-based resin component (A) + 20 ° C. or more, the melting point of the organic fiber (U) −30 ° C. or less, particularly preferably the melting peak temperature (Tm) +30 of the propylene-based resin component (A). The melting point of the organic fiber (U) is −40 ° C. or lower. In the injection step (B), by setting the temperature of the fiber composite polypropylene resin composition for foam molding in the molten state or semi-molten state obtained from the melting step (A) to such a temperature range, the gold of the organic fiber Since there is little melting due to shear heat generation during in-mold flow, the fiber composite polypropylene-based resin foam molded article has a sufficient reinforcing effect by organic fibers (c), and an effect that a good foaming ratio can be obtained. That is, when the temperature is lower than the melting peak temperature of the propylene resin component (a), the fluidity and the expansion ratio tend to decrease, and when the melting point of the organic fiber (c) exceeds −10 ° C., the organic fiber (c) melts. However, the expansion ratio may be reduced.

Here, the temperature of the fiber composite polypropylene resin composition for foam molding referred to here is the temperature measured with a thermocouple for the fiber composite polypropylene resin composition for foam molding in the injection cylinder in the melting step (A), or injection. This refers to the temperature at which the fiber composite polypropylene resin composition for foam molding just after being measured with a thermocouple. Moreover, you may regard the injection cylinder preset temperature as the temperature of the fiber composite polypropylene-type resin composition for foam molding. The control method can be determined, for example, by setting the injection cylinder temperature in the melting step (A).

(4) Condition (Ci)
The foaming step (C) satisfies the following condition (Ci).
Condition (C-i)
After performing the injection step (B), the mold is retreated to the mold cavity clearance (T1) corresponding to the shape position of the foamed molded product from which the movable mold can be obtained in the foaming step (C), and the mold is expanded by the expansion pressure by the foaming agent. Fill the cavity of the mold cavity.
The mold cavity clearance T1 corresponding to the shape position of the foamed molded product obtained in the foaming step (C) is usually 1.5 mm to 8 mm, preferably 1.5 mm to 5.0 mm, 2.0 mm to 4.0 mm. More preferred. By setting it in such a range, the weight can be reduced from the current weight, and there is an effect that uniform foamability can be obtained with respect to the surface. The mold cavity clearance (T1) corresponds to the shape position of the obtained foamed molded product, that is, the thickness of the obtained foamed molded product.

  When the movable mold is retracted (moved) in the foaming step (C), it is preferable to use the “electric movable mold” rather than the “hydraulic movable mold”. The advantage of using an electric movable type is that differences in work environment temperature and operating time are less likely to occur in the movement of the movable type, and products that are more accurate than using a hydraulic movable type can be obtained continuously. Have

In the injection step (B) of the mold opening injection foaming method using the chemical foaming agent, which is the manufacturing method of the present invention, gas is previously supplied to the mold cavity with the aim of further improving the appearance of the product by preventing gas diffusion from the molten resin. A mold counter pressure method in which the molten resin is injected and filled in the injected state may be added. As the kind of gas to be injected, air, N ₂ , CO ₂ or the like can be used, and a mixed gas thereof may be used. Further, since a chemical foaming agent is used, the foaming gas pressure in the molten resin is 0.4 to 0.5 MPa, which is lower than when a physical foaming agent is used, and the necessary gas pressure to be injected into the mold cavity is 0.4 to 0.00. It can be handled with a safe low-pressure gas higher than 5 MPa and lower than 1 MPa.

  In the production method of the present invention, any one of a skin decorative molding method, a multilayer molding method, and a sandwich molding method may be combined in order to improve product design.

Hereinafter, the characteristic of the molded object of this invention is demonstrated.
(1) Surface hardness Normally, the surface hardness of the foamed molded product decreases as the expansion ratio increases. The surface hardness of the foamed molded product is indicated by type A durometer hardness. When the hardness is low, a soft touch, that is, a high touch is obtained. Preferably, the A hardness at the maximum magnification is 80 or less.
In the present application, the type A durometer hardness is specifically determined by the method described in the example section described later.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In Examples and Comparative Examples, various physical properties of the polypropylene resin composition or its constituent components were measured and evaluated according to the following evaluation methods.

1. Evaluation Method (1) Preparation of Test Piece and Maximum Foaming Ratio Using an injection molding machine (“α-300” manufactured by FANUC), a test piece was prepared by the following mold opening injection molding method.
First, a chemical foaming agent master batch (Polyslen EE65C manufactured by Eiwa Kasei Co., Ltd., gas generation amount: 85 to 105 ml / 2 g (220 ° C. constant temperature) as a chemical foaming agent (d) per 100 parts by weight of the fiber composite polypropylene resin composition for foam molding. Lower x 20 min)) was added in 3 parts by weight dry blend and melted in the melting step (A). The temperature of each heating zone of the heating cylinder in the melting step (A) is set to 210 ° C., 210 ° C., 210 ° C., 180 ° C. in order from the front end portion to the rear portion, and the molten state or half obtained from the melting step (A) The temperature of the molten fiber composite polypropylene resin composition for foam molding was set to 210 ° C.
Next, in the injection step (B), an initial mold is used by using a mold (mold shape: flat plate (400 mm × 200 mm), mold temperature: 40 ° C.) composed of a fixed mold and a movable mold capable of moving forward and backward. The mold cavity clearance (T0) is set to 2.0 mm, and the foam composite fiber composite polypropylene resin composition in a molten state or a semi-molten state at 210 ° C. obtained from the melting step (A) is injected at an injection speed of 120 mm / The mold cavity was injection filled as seconds.

After performing the injection step (B), mold opening was started 0.5 seconds after completion of injection filling, and the foaming step (C) was performed. In the foaming step (C), the mold cavity clearance (T1) corresponding to the shape position of the obtained foamed molded product is 1.5 to 0 times the initial mold cavity clearance (T0) (2.0 mm). The movable mold is retracted so that the distance between the movable mold and the stationary mold is 3.0 times in increments of 0.25 times (3.0 mm to 6.0 mm between the movable mold and the stationary mold), and the cavity of the mold cavity is filled with the expansion pressure of the foaming agent. The specimen was obtained after cooling for 25 seconds.
Foaming ratio (foaming ratio: T1 / T0) of “mold cavity clearance (T1) corresponding to the shape position of the obtained foamed molded product” to “mold cavity clearance (T0)” in the injection step (B) The expansion ratio of the molded product obtained at the time of the maximum mold cavity clearance (T1) in which the shape of the molded product can reproduce the cavity shape was defined as the maximum foaming magnification.

(2) Hardness (Type A durometer hardness: A hardness)
Pressing the pressure reference surface of the hardness tester at the center of the molded product at the maximum expansion ratio obtained in (1) above against the surface of the molded product without impact while keeping it horizontal to the molded product surface. The surface of the molded product was in close contact with the surface of the molded product, and the maximum value of the pointer of the indicating device was read within 1 second. The apparatus used was an Asker rubber hardness meter type A manufactured by Kobunshi Keiki Co., Ltd.

(3) Identification of component (A-A) and component (A-B) in propylene-based resin component (A):
In the propylene-based resin component (a), the identification of the component (A-A) and the component (A-B), the identification of the ethylene content in the component (A-A) and the component (A-B), and the like are described above. Fractionation using temperature rising elution fractionation (TREF) and measurement of ethylene content by ¹³ C-NMR were performed.

(4) Melting peak temperature (Tm) of the propylene-based resin component (a):
Using a Seiko Instruments DSC6200 model, take 5.0 mg of sample, hold it at 200 ° C for 5 minutes, crystallize it to 40 ° C at a rate of 10 ° C / min. Measured after melting.

(5) Peak of tan δ curve of propylene resin component (a):
It measured by the solid viscoelasticity measurement shown below. In addition, the sample cut out into the strip shape of 10 mm width x 18 mm length x 2 mm thickness from the 2 mm-thick sheet | seat injection-molded on condition of the following was used.
1) Solid viscoelasticity measurement device: ARES (manufactured by Rheometric Scientific)
Frequency: 1Hz
Measurement temperature: From -60 ° C. until the sample melts.
Strain: 0.1 to 0.5% range 2) Sample preparation Molding machine: TU-15 injection molding machine manufactured by Toyo Machine Metal Co., Ltd. Molding machine set temperature: 80, 80, 160, 200, 200, 200 ° C. from below the hopper
Mold temperature: 40 ℃
Injection speed: 200 mm / sec (speed in the mold cavity)
Injection pressure: 800kgf / cm2
Holding pressure: 800 kgf / cm2
Holding time: 40 seconds
Mold shape: Flat plate (2mm thickness, 30mm width, 90mm length)

(6) Melt flow rate (MFR)
Measured in accordance with JIS K7210: 1999, Method A, Condition M (230 ° C., 2.16 kg load). The unit is g / 10 minutes.

2. Raw material (1) Propylene resin component (A):
The following commercially available resins were used.
PP-A: Wellnex RMG02 (manufactured by Nippon Polypro)
Metallocene catalyst, MFR (230 ° C., 2.16 kg load) 20 g / 10 min, ethylene content 5.9 wt%, melting peak temperature (Tm) = 130 ° C.
This PP-A is composed of a propylene-ethylene random copolymer (A) in the first step (1.8% by weight), a composition ratio of 56% by weight, and a propylene-ethylene random copolymer (A) in the second step. -B) has an ethylene content of 11% by weight (9.2% by weight relative to the ethylene content of (A)), a composition ratio of 44% by weight, and the tan δ curve has a single peak at -11 ° C.

PP-B: Newcon BC10HRF (Nippon Polypro)
Propylene-ethylene block copolymer resin, Ziegler catalyst, MFR (230 ° C., 2.16 kg load) 100 g / 10 min, melting peak temperature (Tm) = 161 ° C.
This PP-B is composed of the ethylene content of the first step propylene homopolymer (A-A) 0% by weight, the composition ratio 80% by weight, the second step propylene-ethylene random copolymer (A-B) ethylene. The content was 36% by weight (36% by weight relative to the ethylene content of (A-A)), and the composition ratio was 20% by weight.

PP-C: Novatec MG3F (manufactured by Nippon Polypro)
Propylene-ethylene random copolymer resin, Ziegler catalyst, MFR (230 ° C., 2.16 kg load) 8 g / 10 min, melting peak temperature (Tm) = 144 ° C.
In this PP-C, the ethylene content of the propylene-ethylene random copolymer (A) in the first step was 2.5% by weight and the composition ratio was 100% by weight, and the second step was not performed.

(2) Elastomer (I)
E-A: (Ethylene octene rubber: EG8200 manufactured by Dow) Density (0.870) MFR = 10 g / 10 min.
EB: (ethylene octene rubber: EG8450 manufactured by Dow): density (0.902) MFR = 6 g / 10 min.

(3) Organic fiber (U)
F-A: Polyester fiber (P903AL BHT1670T250 manufactured by Teijin Ltd.) Single yarn fineness 6.68 dtex, tensile strength 7 cN / dtex, average fiber diameter 24 μm, length 10 mm, melting point 260 ° C., polar resin (polyglycidyl ether epoxy resin) Treated and the polar resin is attached.
FB: Glass fiber: (T480H manufactured by Nippon Electric Glass Co., Ltd.) Fiber diameter 10 μm, length 8 mm

3. Examples and Comparative Examples [Examples 1 to 6 and Comparative Examples 1 to 9]
(1) Manufacture of a fiber composite polypropylene resin composition for foam molding After blending the propylene resin component (a) and the elastomer (I) together with the following additives in the ratio shown in Table 3, and mixing with a Henschel mixer, It is melt plasticized with a twin screw extruder (Tex30 manufactured by Nippon Steel Works), introduced into a crosshead die having an impregnation tank connected to the tip of the extruder together with organic fibers (U), and melted by a pultrusion method. Was impregnated with continuous organic fibers. At this time, the discharge amount and the strand take-up speed were adjusted so that the ratio of the propylene-based resin component (A) to the organic fiber (U) was as shown in Table 3. The taken strand was pelletized with a cut length of 10 mm to obtain resin pellets.
The additive is 0.1 part by weight of IRGANOX 1010 manufactured by BASF and 0.1% by weight of IRGAFOS 168 manufactured by BASF with respect to 100 parts by weight of the total fiber composite polypropylene resin composition for foam molding comprising the components (a) to (c). Each of 05 parts by weight was blended.

(2) Molding of Fiber Composite Polypropylene Resin Composition for Foam Molding 100 parts by weight of the obtained resin pellets are dry blended with 3 parts by weight of the above chemical foaming agent, injection molded under the above conditions, and fiber for foam molding Various test pieces of the composite polypropylene resin composition were used.

(3) Evaluation Performance evaluation was performed on the above molded product. The results are shown in Table 3.

Evaluation From the results shown in Table 3, Examples 1 to 6 satisfying the invention requirements of the resin composition of the present invention and the foamed molded product thereof are shown to have a high expansion ratio and low hardness. That is, Examples 1 to 6 show foamed molded articles having an expansion ratio of 2.5 times or more and an A hardness of 80 or less.
On the other hand, in the comparative examples that do not satisfy the specific matters of the invention, the resin compositions having the compositions shown in comparative examples 1 to 9 and the foamed molded articles thereof are inferior in terms of expansion ratio and low hardness.
In Comparative Examples 1 and 3, since the blending amount of the organic fiber (U) was insufficient, the effect of improving the expansion ratio by the organic fiber was not obtained.
In Comparative Examples 2 and 5, since the blending amount of the elastomer (I) is insufficient, the maximum foaming ratio is low and insufficient.
In Comparative Example 4, since the amount of fibers was too large, the fluidity was lowered and the expansion ratio was lowered. In Comparative Example 6, the amount of rubber was too large, resulting in poor cutting during granulation, and molding resin pellets could not be obtained. In Comparative Example 7, the expansion ratio is 2.5 times or more, but the surface hardness becomes high because the glass fiber itself has strength.
In Comparative Examples 8 and 9, the expansion ratio is less than 2.5 times. This is probably because the crystallization temperature of the propylene resin composition was high and cell growth was suppressed during foaming.

The foam-molded fiber composite polypropylene resin composition of the present invention provides a foamed molded product having high foaming, low hardness and high touch.
Therefore, automotive interior parts such as instrument panels, glove boxes, console boxes, door trims, armrests, grip knobs, various trims, pillars, etc., electrical and electronic equipment parts such as vacuum cleaners, various industrial parts, and housing equipment It can be suitably used for applications such as parts, and is very useful industrially.

Claims (5)

Propylene-based resin component (a) polymerized with a metallocene catalyst (a) 40 to 85% by weight, elastomer (a) 15 to 60% by weight, and (a) and (a) 100 parts by weight in total, And 5 to 55 parts by weight of a fiber composite polypropylene resin composition for foam molding.
Propylene-based resin component (a): having the requirements specified in the following (a-i) to (a-iv).
(A-i): In the first step, propylene alone or a propylene-ethylene random copolymer component (A-A) having an ethylene content of 7% by weight or less is 30 to 95% by weight; in the second step, the component (a- A propylene-ethylene random copolymer component (A-B) containing 3 to 20% by weight of ethylene more than A) is obtained by sequential polymerization of 70% to 5% by weight (provided that (A-A) And (A-B) is 100% by weight).
(A-ii): Melting peak temperature (Tm) measured by DSC method is 110 ° C to 150 ° C.
(A-iii): In the temperature-loss tangent curve obtained by solid viscoelasticity measurement, the tan δ curve has a single peak at 0 ° C. or lower.
(A-IV): The melt flow rate (MFR: 230 ° C., 2.16 kg load) of the entire propylene resin component (A) is 0.5 g / 10 min to 200 g / 10 min.

Elastomer (A): having the requirements specified in (I-i) below (I-i) Density is 0.86-0.910 g / cm3 and melt flow rate (MFR: 230 ° C., 2.16 kg load) 0.5g / 10min to 80g / 10min

Organic fiber (c): It has the requirements specified in the following (c).
(Ui): polyester fiber or polyamide fiber having a melting point of 245 ° C. or higher   The fiber composite polypropylene resin composition for foam molding according to claim 1, wherein the organic fiber (U) is an organic fiber to which a polar resin is attached. A melt process (A) in which a chemical foaming agent (D) is added and melted to the fiber composite polypropylene resin composition for foam molding according to claim 1 or 2, and a molten state obtained from the melt process (A) or This is a method for producing a fiber composite polypropylene resin foam molded article having an injection step (B) of injecting and filling a mold cavity with a fiber composite polypropylene resin composition for foam molding in a semi-molten state, and a foaming step (C). The manufacturing method is a mold opening injection molding method, the melting step (A) satisfies the following condition (A-i), and the injection step (B) is performed under the following conditions (Bi) to (B-ii). And the foaming step (C) satisfies the following condition (Ci): A method for producing a fiber composite polypropylene resin foam molded article.
Condition (A-i)
In the melting step (A), 0.005 to 8 parts by weight of the chemical foaming agent (d) is added to 100 parts by weight of the fiber composite polypropylene resin composition for foam molding and melted.
Condition (B-i)
The mold used in the injection step (B) is composed of a fixed mold and a movable mold capable of moving forward and backward, and is smaller than the mold cavity clearance (T1) corresponding to the shape position of the obtained foamed molded body. In the mold cavity clearance (T0), the molten or semi-molten foam composite fiber composite polypropylene resin composition obtained from the melting step (A) is injection-filled into the mold cavity.
Condition (B-ii)
In the injection step (B), the temperature of the foam composite fiber composite polypropylene resin composition for foam molding obtained from the melting step (A) is [melting peak temperature of propylene resin component (a) ( Tm)] or more and [melting point of organic fiber (a) −10 ° C.] or less.
Condition (C-i)
After performing the injection step (B), the mold is retreated to the mold cavity clearance (T1) corresponding to the shape position of the foamed molded product from which the movable mold can be obtained in the foaming step (C), and the mold is expanded by the expansion pressure by the foaming agent. Fill the cavity of the mold cavity.   The ratio (foaming ratio: T1 / T0) of the mold cavity clearance (T1) corresponding to the shape position of the obtained foamed molded product to the mold cavity clearance (T0) in the injection step (B) is 1.05 to 1.05. The manufacturing method of the fiber composite polypropylene resin foaming molding of Claim 3 which exists in the range of 3.0.   The foaming molding obtained by the manufacturing method of the fiber composite polypropylene resin foaming molding of Claim 3 or 4.

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