JP2010270243A - Polypropylene-based resin in-mold foam molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylene-based resin in-mold foam molded product having improved flame retardancy in a black polypropylene-based resin in-mold foam molded product containing carbon black. <P>SOLUTION: The polypropylene-based resin in-mold foam molded product comprises polypropylene-based resin foamed particles containing 0.1-10 wt.% of carbon black and a 3-6C polyhydric alcohol having ≥3 hydroxy groups. The polypropylene-based resin in-mold foam molded product exhibits self-extinguishability or slow combustibleness in a combustion testing method stipulated by FMVSS302. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a polypropylene resin in-mold foam-molded article having flame retardancy composed of polypropylene resin foam particles.

  Polypropylene resin foam-in-mold molded product obtained by filling polypropylene resin foamed polypropylene resin foam into a mold for in-mold foam molding and then heat-sealing them is already a packaging material. It is used for a wide range of applications such as cushioning materials, heat insulating materials, building materials, and automotive parts. Among these uses, in the field of building materials and automobile parts, it is required to have flame retardancy, and a polypropylene system containing a flame retardant and a flame retardant aid in the resin as necessary. In-mold foam moldings using resin foam particles and polypropylene resin foam particles have been proposed (for example, Patent Documents 1 and 2). However, the polypropylene resin-in-mold foam-molded products containing these flame retardants and flame retardant aids have problems such as a decrease in mechanical strength and contamination of the mold caused by bleeding from the resin. Halogen flame retardants and phosphorus flame retardants are also said to have environmental compatibility problems, and it is preferable that flame retardancy can be expressed without using these flame retardants and flame retardant aids.

  In addition, polypropylene resin foam particles colored from the viewpoint of appearance and polypropylene resin in-mold foam moldings using the polypropylene resin foam particles may be required. In particular, blackened polypropylene in the field of automobile parts and the like. Therefore, polypropylene resin foam particles that have been blackened with carbon black and the in-mold foam molding have been proposed (for example, Patent Document 3). However, since carbon black lowers the flame retardancy, it requires a larger amount of flame retardant and flame retardant aid than when carbon black is not added, and problems such as a decrease in mechanical strength are apparent. It will become.

  On the other hand, Patent Document 4 discloses a void that is used for drainage materials for civil engineering, architecture, horticulture, etc., has excellent hydrophilicity, has quick water wetting, and exhibits good water permeability from the beginning when the water contacts the molded body. For the purpose of providing a water-permeable foamed molded article having the above, a technique for incorporating or applying a hydrophilicity imparting agent to the foamed molded article is disclosed. Examples of the hydrophilicity-imparting agent include hydrophilic liquids and surfactants such as ethylene glycol, glycerin, and polyethylene glycol.

JP-A-7-309967 JP-A-10-147661 JP-A-7-300537 Japanese Patent Laid-Open No. 8-59875

  An object of the present invention is to provide a polypropylene resin-in-mold foam-molded product having improved flame retardancy in a black polypropylene-based resin mold-in-mold foam-molded product containing carbon black.

  As a result of intensive investigations, the present inventors have made 3 to 6 carbon atoms typified by glycerin, which is considered to have reduced flame retardancy when added to polypropylene resin expanded particles containing carbon black. Moreover, by adding a predetermined amount of polyhydric alcohol having 3 or more hydroxyl groups, it was found that the flame retardancy is unexpectedly improved, and the present invention has been completed.

That is, this invention consists of the following structures.
[1] Polypropylene resin in-mold foam composed of polypropylene resin foam particles containing 0.1 to 10% by weight of carbon black and a polyhydric alcohol having 3 to 6 carbon atoms and having 3 or more hydroxyl groups A polypropylene-based resin-mold-in-mold foam-molded article, wherein the polypropylene-series resin-mold-in-mold foam-molded article exhibits self-extinguishing properties or slow-flammability by a combustion test method defined in FMVSS302.
[2] The polypropylene resin in-mold foam molded product according to [1], wherein the molded product density is 5 g / L or more and less than 200 g / L.
[3] The polypropylene resin mold according to [1] or [2], comprising 0.05 to 3% by weight of a polyhydric alcohol having 3 to 6 carbon atoms and 3 or more hydroxyl groups. Foam molded body.
[4] The polypropylene resin in-mold foam molded article according to any one of [1] to [3], wherein the polyhydric alcohol having 3 to 6 carbon atoms and 3 or more hydroxyl groups is glycerin.

  In the FMVSS302 test method, the same amount of the polypropylene resin-in-mold foam-molded article comprising the carbon black of the present invention and the polypropylene resin foamed particles containing polyhydric alcohol having 3 to 6 carbon atoms and 3 or more hydroxyl groups. The flame retardancy is improved as compared with the polypropylene resin in-mold foam-molded product to which only carbon black is added.

  The polypropylene-based resin used in the present invention refers to a resin containing 60% by weight or more, preferably 80% by weight or more of propylene as a monomer component, and may contain a monomer copolymerizable with propylene. It doesn't matter. Specifically, propylene homopolymer, ethylene-propylene block copolymer, ethylene-propylene random copolymer, butene-propylene random copolymer, butene-propylene block copolymer, ethylene-butene-propylene random copolymer Can be illustrated. Among these, ethylene-propylene random copolymer having an ethylene content of 0.1 wt% to 10 wt%, or a total of 0.1 wt% and 10 wt% of ethylene and 1-butene, and An ethylene-butene-propylene random copolymer containing 0.5% by weight or more of 1-butene is more preferable from the viewpoints of moldability and mechanical strength.

  These polypropylene resins may be non-cross-linked or cross-linked, but are preferably non-cross-linked from the viewpoint of recycling.

  The melting point of the polypropylene resin that can be used in the present invention is preferably 130 ° C. or higher and 165 ° C. or lower, and more preferably 135 ° C. or higher and 155 ° C. or lower. When the melting point is less than 130 ° C., heat resistance and mechanical strength tend to be insufficient. Moreover, when melting | fusing point exceeds 165 degreeC, there exists a tendency for it to become difficult to ensure the melt | fusion at the time of in-mold foam molding. Here, the melting point refers to a temperature of 10 to 10 mg of polypropylene-based resin raised from 40 ° C. to 220 ° C. at a rate of 10 ° C./min by a differential scanning calorimeter, and then cooled to 40 ° C. at a rate of 10 ° C./min. The peak temperature of the endothermic peak in the DSC curve obtained when the temperature is increased again to 220 ° C. at a rate of 10 ° C./min.

  The melt index (hereinafter referred to as MI value) of the polypropylene resin that can be used in the present invention is preferably 0.5 g / 10 min to 30 g / 10 min, more preferably 2 g / 10 min to 20 g / min, More preferably, it is 5 g / 10 min or more and 10 g / 10 min or less.

  When the MI value is less than 0.5 g / 10 minutes, it is difficult to obtain polypropylene-based resin expanded particles with a high expansion ratio. When the MI value exceeds 30 g / 10 minutes, the bubbles of the polypropylene-based resin expanded particles easily break, The open cell ratio of the resin foam particles tends to increase.

  In the present invention, the MI value is a value measured at a temperature of 230 ° C. and a load of 2.16 kg in accordance with JIS K7210.

  Further, two or more types of polypropylene resins having different melting points and MI values may be mixed to obtain the above range.

  Carbon black in the present invention is 0.1 wt% or more and 10 wt% or less, preferably 1 wt% or more and 7 wt% or less, more preferably 3 wt% or more and 5 wt% or less in the expanded polypropylene resin particles. is there. When the carbon black is less than 0.1% by weight, the degree of blackness is thin when it is made into a polypropylene resin-molded in-mold foam, and when it exceeds 10% by weight, the combustion speed is increased and the FMVSS302 combustion test is not cleared.

  There is no restriction | limiting about the kind of carbon black used for this invention, Ketjen black, thermal black, furnace black, channel black, lamp black, gas black, roller black, acetylene black, etc. can be used.

  The particle size of carbon black used in the present invention is not particularly limited, but the particle size is preferably 0.1 nm or more and 10,000 nm or less. If it is less than 0.1 nm, it tends to be difficult to handle, and if it exceeds 10,000 nm, the dispersibility in the resin tends to be poor and color unevenness tends to be caused. In addition, the size of the structure in which the particles are aggregated may be approximately several tens nm to several hundreds nm.

  Specific examples of the polyhydric alcohol having 3 to 6 carbon atoms and 3 or more hydroxyl groups used in the present invention include glycerin, 1,2,4-butanetriol, diglycerin, pentaerythritol, and trimethylolpropane. Sorbitol, D-mannitol, erythritol, hexanetriol, xylitol, D-xylose, inositol, fructose, galactose, glucose, mannose and the like. Especially, it is preferable that it is 1 or more types chosen from glycerol, diglycerol, pentaerythritol, a trimethylol propane, sorbitol, and D-mannitol, More preferably, it is glycerol. Glycerin also has a feature that it has a small environmental impact because it exhibits easy degradability even when it is eluted into wastewater during production. In general, it is easy to obtain and inexpensive, which is preferable.

  In general, so-called hydrophilic substances having a large number of hydroxyl groups in the molecule are slightly inferior in compatibility with polypropylene resins. However, polyhydric alcohols having 3 to 6 carbon atoms and 3 or more hydroxyl groups used in the present invention. Then, after blending with a polypropylene resin, kneading with an extruder and dispersion in the process of producing polypropylene resin particles by a strand cutting method results in relatively good dispersion, so that strand breakage and molten resin feed are not possible. There is a tendency for troubles such as stability to occur less frequently. Furthermore, there is a tendency that polypropylene-based resin expanded particles having uniform bubbles and small variation in magnification are obtained. A polypropylene resin in-mold foam molded article obtained by in-mold foam molding using the polypropylene resin foam particles exhibits good flame retardancy.

  The addition amount of the polyhydric alcohol having 3 to 6 carbon atoms and 3 or more hydroxyl groups is preferably 0.05 to 3% by weight, more preferably 0.07 to 1% by weight. Or less, more preferably 0.1 wt% or more and 0.7 wt% or less. If the addition amount of the polyhydric alcohol having 3 to 6 carbon atoms and 3 or more hydroxyl groups is less than 0.05% by weight, it may be difficult to improve the flame retardancy of the polypropylene resin expanded particles. When the addition amount exceeds 3% by weight, the flame retardancy tends to decrease.

  When glycerin is used as the polyhydric alcohol having 3 to 6 carbon atoms and 3 or more hydroxyl groups, the amount added is preferably 0.05% by weight or more and 0.8% by weight or less. More preferably, it is 0.05 weight% or more and 0.5 weight% or less, Most preferably, it is 0.05 weight% or more and 0.3 weight% or less.

  Here, the content of the polyhydric alcohol having 3 to 6 carbon atoms and 3 or more hydroxyl groups in the polypropylene resin particles and the polypropylene resin expanded particles is determined by HPLC using ELSD (evaporation light scattering) as a detector. It can be quantified using an apparatus (for example, a high performance liquid chromatograph manufactured by Shimadzu Corporation: Prominence High Pressure Gradient System).

  In addition to carbon black, a polyhydric alcohol having 3 to 6 carbon atoms and 3 or more hydroxyl groups, the foamed polypropylene resin particles of the present invention include, as necessary, a foam nucleating agent, a hydrophilic substance, a compatibilizing agent, Various additives such as antistatic agents, colorants, stabilizers, weathering agents, flame retardants and the like can be used.

  Foam nucleating agent refers to a substance that promotes the formation of cell nuclei during foaming. For example, inorganic substances such as talc, calcium carbonate, silica, kaolin, barium sulfate, calcium hydroxide, aluminum hydroxide, aluminum oxide, titanium oxide, and zeolite Substances, fatty acid metal salts such as calcium stearate and barium stearate can be mentioned, and these can be used alone or in combination of two or more. Among these, talc, calcium carbonate, and calcium stearate are preferable. Further, it is desirable that the particle size distribution is sharp.

  Moreover, in order to improve the expansion ratio of the polypropylene resin expanded particles, it is also possible to use a hydrophilic substance other than polyhydric alcohol having 3 to 6 carbon atoms and having 3 or more hydroxyl groups. A hydrophilic substance is a substance that increases the amount of water impregnated in a resin when producing expanded particles. Specific examples include sodium chloride, calcium chloride, magnesium chloride, borax, calcium borate, and zinc borate. Water-soluble inorganic substances such as melamine, isocyanuric acid, water-absorbing organic substances such as melamine / isocyanuric acid condensate, etc .; hydrophilic polymers such as polyethylene glycol and fatty alcohols having 12 to 18 carbon atoms such as cetyl alcohol and stearyl alcohol Is mentioned. Of these, polyethylene glycol and melamine are preferred.

  Polypropylene resin is usually melted beforehand using an extruder, kneader, Banbury mixer, roll, etc. so that it can be easily used for foaming, and has a desired shape such as a cylinder, ellipse, sphere, cube, cuboid, etc. Particle-shaped polypropylene resin particles are used. The average particle weight of the polypropylene resin particles is preferably 0.5 to 3.0 mg, more preferably 0.5 to 2.0 mg, and still more preferably 0.5 to 1.5 mg. At this time, it is preferable to melt and knead together carbon black, a polyhydric alcohol having 3 to 6 carbon atoms and 3 or more hydroxyl groups, and other additives to be added as necessary to obtain polypropylene resin particles. . Carbon black, a polyhydric alcohol having 3 to 6 carbon atoms and 3 or more hydroxyl groups, and other additives that are added as necessary may be added as they are or may have a concentration of 10% to 60% in advance. A master batch may be added.

  The polypropylene resin expanded particles obtained as described above are dispersed in a dispersion medium such as water while stirring and flowing the contents together with the foaming agent in a sealed pressure vessel, and more than the softening temperature of the polypropylene resin. Heat to the melting point of the resin from −10 ° C. to the melting point + 10 ° C., hold at that temperature (hereinafter sometimes referred to as the foaming temperature) for a certain period of time, then open one end of the container and foam the pressure inside the container. While maintaining the pressure higher than the vapor pressure of the agent, the polypropylene resin particles and the dispersion medium are released into a lower pressure atmosphere (usually under atmospheric pressure) than inside the container to expand the polypropylene resin particles, and the polypropylene resin Expanded particles can be obtained.

  Examples of the blowing agent include aliphatic hydrocarbons such as butane, propane, pentane, hexane, heptane, cyclobutane, and cyclopentane, and inorganic substances such as air, nitrogen, carbon dioxide, helium, neon, argon, and water. Two or more of these may be used in combination. In addition, when using water as a foaming agent, the water of the dispersion medium used when obtaining a foaming agent can be utilized.

  The amount of the foaming agent used is appropriately adjusted in relation to the expansion ratio and expansion temperature of the expanded particles to be obtained. The expansion temperature is 1.5 to 7 MPa (G) during or after heating. It is preferable to press-fit into the container so as to be in the pressure range, or to prepare in advance an amount that indicates the pressure at the foaming temperature before heating.

  A dispersant can be used to prevent fusion of the resin particles when the polypropylene resin particles are dispersed in the dispersion medium and heated to the foaming temperature. Examples of such a dispersant include calcium phosphate, aluminum oxide, titanium oxide, aluminum hydroxide, kaolin, talc, mica, and barium sulfate. Although there is no restriction | limiting in particular in the average particle diameter of a dispersing agent, 0.001 or more and 50 micrometers or less are preferable, More preferably, they are 0.01 micrometer or more and 20 micrometers or less. When it is less than 0.001 μm, it may be difficult to handle, and when it exceeds 50 μm, the performance as a dispersant tends to decrease.

  The addition amount of the dispersant is appropriately adjusted so as to prevent the fusion of the polypropylene resin particles depending on the foaming temperature, the addition amount of the foaming agent, and the type of the foaming agent. The amount is preferably 0.01 parts by weight or more and 5 parts by weight or less with respect to 100 parts by weight. If the amount is less than 0.01 part by weight, the performance as a dispersant may be reduced, and fusion between polypropylene resin particles may be observed. If the amount exceeds 5 parts by weight, no significant improvement in the anti-fusing performance is observed.

  A dispersing aid can be used in combination with the dispersing agent. Examples of the dispersion aid include surfactants such as sodium alkylbenzene sulfonate, sodium alkyl sulfate, sodium n-paraffin sulfonate, sodium oleate, polyoxyethylene alkylphenyl ether, lauryltrimethylammonium chloride, and fatty acid diethanolamide. These 1 type (s) or 2 or more types can be used conveniently.

  The amount of such a dispersion aid added is appropriately adjusted depending on the foaming temperature, the amount of foaming agent added, the type of foaming agent, the type of dispersant, and the amount added. 0.001 to 2 parts by weight is preferable with respect to 100 parts by weight. If the amount is less than 0.001 part by weight, the performance as a dispersion aid may be reduced and the resin particles may be fused. If the amount exceeds 2 parts by weight, no significant improvement in the anti-fusing performance is observed.

  Although there is no restriction | limiting in particular in the production method of the polypropylene resin expanded particle of this invention, It can produce by the following well-known methods. That is, it can be obtained by melt-kneading a polypropylene resin, carbon black, a polyhydric alcohol having 3 to 6 carbon atoms and 3 or more hydroxyl groups and various additives as required. If necessary, the polypropylene resin particles are dispersed in a dispersion medium together with a foaming agent in a closed container together with a dispersant and a dispersion aid, and the temperature of the sealed container is increased, and the polypropylene resin particles are converted into a polypropylene resin. Although the temperature is equal to or higher than the softening temperature of the particles, the foaming agent is press-fitted in at least one stage before, during, or after the temperature rise as necessary. Polypropylene resin foam particles can be obtained by releasing the polypropylene resin particles together with the dispersion medium at a temperature equal to or higher than the softening temperature of the polypropylene resin particles in a low-pressure atmosphere (usually under atmospheric pressure) from the inside of the closed container.

  In addition, when releasing in a low-pressure atmosphere (usually under atmospheric pressure) from the inside of the above-mentioned sealed container, the pressure in the sealed container is maintained, for example, with an inorganic gas such as nitrogen, air, carbon dioxide, etc. so as not to decrease. It is preferable.

  The polypropylene resin foam particles obtained as described above can be used for in-mold foam molding as they are, but by applying an internal pressure in the polypropylene resin with an inorganic gas such as air or nitrogen, and heating. Further, a so-called two-stage foaming method for further increasing the foaming ratio may be performed.

  The polypropylene resin-in-mold foam-molded article comprising the polypropylene resin foam particles of the present invention is made of polypropylene resin foam particles, air, oxygen, nitrogen, carbon dioxide, or a mixture selected from these as required. After applying a predetermined internal pressure within the particles by pressure aging with an inorganic gas that is a gas, the polypropylene-based resin foamed particles are left as they are in a mold for molding that can be closed but cannot be sealed, or in a pressure-compressed state Filled with, generally heated polypropylene resin foam particles with water vapor at a temperature near the melting point of the polypropylene resin, the particles are fused together, and then cooled to obtain a molded product, obtained by an in-mold foam molding method be able to.

  The density of the obtained polypropylene resin in-mold foam molding is preferably 5 g / L or more and 200 g / L or less, and more preferably 10 g / L or more and 150 g / L or less. This range is preferable because the mechanical strength is not reduced by the bursting of bubbles, and the weight can be reduced.

  The in-mold foam molded article comprising the polypropylene resin foamed particles of the present invention is excellent in flame retardancy. Specifically, the polypropylene resin in-mold foam-molded article of the present invention exhibits self-extinguishing properties or slow-flammability by a combustion test method defined in FMVSS302. The combustion test method defined in FMVSS 302 is performed as follows.

  A test piece of 365 mm × 102 mm × 12 mm is cut out from the foamed molded product in the polypropylene resin mold, and from one end side (a side) in the longitudinal direction of the test piece, 38 mm is an A marked line, and 254 mm from the A marked line is a B marked line. The other end is held with a clamp or the like so that the test piece is horizontal. The burner's mouth is 19 mm below the lower surface of the test piece and the flame height is 38 mm. The flame is applied to one end (a side) of the test piece for 15 seconds, and then the burner's flame is extinguished. The time measurement is started with a stopwatch, and if the fire extinguishes within 50 mm before the flame reaches the A mark or within 60 seconds after passing the A mark, When the combustion speed is 100 mm / min or less until exceeding the line B and reaching the mark B, or when the mark B is not reached, the mark A exceeds the mark A and extinguishes the fire.

  In addition, since the polypropylene-based resin-molded foam-molded article of the present invention is lightweight and has little thermal change, it can be used in a wide range of applications such as packaging materials, cushioning materials, heat insulating materials, building materials, and automotive parts.

  Next, the polypropylene resin foamed particles of the present invention and the polypropylene resin in-mold foam-molded product made of the polypropylene resin particles will be described in more detail with reference to examples. “Parts” and “%” are based on weight unless otherwise specified.

<Foaming ratio>
Ethanol is placed in a 200 ml graduated cylinder, and then the expanded polypropylene resin particles are precisely weighed. The volume increment is read with the graduated cylinder, and the density of the expanded polypropylene resin particles is calculated. The density of the polypropylene resin was 0.9 g / ml, and the density of the polypropylene resin particles was divided by the density of the polypropylene resin foam particles to obtain the expansion ratio.

<Molded body density>
The vertical, horizontal and thickness dimensions of the molded body were measured, and the weight was measured to calculate the density.

<Flame retardance>
A test piece of 365 mm × 102 mm × 12 mm was cut out from the molded body, and a combustion test defined in FMVSS 302 was performed. That is, from one end side (a side) in the longitudinal direction of the test piece, 38 mm was set as an A mark line, 254 mm from the A mark line was set as a B mark line, and the other end side was held by a clamp or the like so that the test piece was horizontal. . The burner's mouth is 19 mm below the lower surface of the test piece and the height of the flame is 38 mm. The flame is applied to one end (a side) end of the test piece for 15 seconds, and then the burner's flame is extinguished. Then, the time measurement was started with a stopwatch and evaluated according to the following criteria.
A: Fire extinguished within 50 mm before the flame reaches the A mark or within 60 seconds after passing the A mark (self-extinguishing)
○: Exceeds the A mark and reaches the B mark, or if it does not reach the B mark, the burning speed until exceeding the A mark and extinguishes is 100 mm / min or less. If it does not reach the B mark line, or if it does not reach the B mark line, the burning rate to exceed the A mark line and extinguish the fire exceeds 100 mm / min.

(Examples 1-12)
<Preparation of polypropylene resin particles>
Polypropylene resin, carbon black, polyhydric alcohol having 3 to 6 carbon atoms and 3 or more hydroxyl groups, and a resin additive were mixed so as to have the amounts shown in Table 1. This mixture was charged with an extruder of 50 mmφ, melted and kneaded, discharged into a strand, cooled with water, and then cut with a pelletizer to obtain polypropylene resin particles. In addition, at the time of cutting, it adjusted so that the particle weight of this polypropylene resin particle might be 1.2 mg / grain.

<Preparation of expanded polypropylene resin particles>
100 parts by weight of the polypropylene resin particles produced by the method described above were charged into a 10 liter pressure vessel together with the dispersion medium, dispersant, and dispersion aid shown in Table 1, and then heated to a predetermined temperature. At this time, the foaming agent was charged so that the pressure shown in Table 1 was reached before heating until reaching the predetermined temperature, and after reaching the predetermined temperature as necessary. Thereafter, while maintaining the internal pressure of the container with nitrogen gas, the valve under the pressure container was opened to release the contents of the pressure container into the atmosphere to obtain polypropylene-based resin expanded particles. Table 1 shows the expansion ratio of the obtained polypropylene resin expanded particles. Thereafter, the polypropylene resin expanded particles are charged into another pressure vessel, air is injected to give a predetermined amount of air internal pressure to the polypropylene resin expanded particles, and then the mixture is introduced into a pressure vessel having a stirring function, and then stirred. Then, water vapor of a predetermined pressure was blown to obtain expanded polypropylene resin particles having a larger expansion ratio than the original expanded polypropylene resin particles. Table 1 shows the expansion ratio of the two-stage expanded polypropylene resin expanded particles.

<Process for producing foamed molded product in polypropylene resin mold>
Next, the obtained polypropylene resin expanded particles were charged into another pressure vessel, and air was injected to apply an internal pressure of 0.2 MPa to the polypropylene resin expanded particles.

  The polypropylene resin expanded particles to which the internal pressure was applied were filled in a 400 mm × 300 mm × 120 mm mold, heated with 0.3 MPa water vapor for 10 seconds, and fused to obtain an in-mold expanded molded body. Table 1 shows the characteristics of the obtained in-mold foam molded article.

(Comparative Examples 1-3)
In the same manner as in Examples 1 to 11, in-mold foam molded articles were obtained with the contents described in Table 1. The obtained in-mold foam molded article is shown in Table 1.

Claims (4)

  A polypropylene resin-in-mold foam-molded article composed of polypropylene resin foam particles containing 0.1 to 10% by weight of carbon black and a polyhydric alcohol having 3 to 6 carbon atoms and having 3 or more hydroxyl groups. A polypropylene-based resin-in-mold foam-molded product, wherein the polypropylene-based resin-mold-in-mold foam-molded product exhibits self-extinguishing properties or slow-flammability by a combustion test method defined in FMVSS302.   The polypropylene resin in-mold foam molded article according to claim 1, wherein the density of the molded article is 5 g / L or more and less than 200 g / L.   The polypropylene resin internal foam molded article according to claim 1 or 2, comprising 0.05 to 3% by weight of a polyhydric alcohol having 3 to 6 carbon atoms and 3 or more hydroxyl groups.   The polypropylene resin in-mold foam-molded article according to any one of claims 1 to 3, wherein the polyhydric alcohol having 3 to 6 carbon atoms and 3 or more hydroxyl groups is glycerin.