JPH1112323A - Propylene-based resin for foaming - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a propylene-based resin capable of providing an extruded foam having >=10 mm wall thickness, >=80% closed-cell ratio, 55% reduction in the closed-cell ratio after 80% compression and 0.009-0.045 g/cm<3> foam density of a single substance. SOLUTION: This propylene-based resin has (a) >=0.021 ratio σy/Es of tensile yield strength σy to tensile modulus Es, (b) >=1.0×10<-4> and <=1.2×10<-3> (1/Pa) equilibrium compliance Je0 at 210 deg.C, (c) >0.1 and <10 g/10 min melt flow rate(MFR) at 230 deg.C, (d) >=0.8×10<5> (Pa.s) zero shear viscosity at 210 deg.C and (e) >=55 J/g energy of fusion ΔH.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to, for example, a cushioning material,
The present invention relates to a foaming propylene-based resin for various foams that can be used as a floating material, a heat insulating material, and the like.

[0002]

2. Description of the Related Art Since polypropylene polymers have high rigidity and high mechanical properties when formed into extruded foams having a high expansion ratio, various developments have been made in recent years. For example, JP-A-7-138323 discloses that
Independent and uniform air bubbles are generated during foam molding, surface appearance,
As a propylene polymer for foaming capable of obtaining a foam having excellent heat resistance with good moldability, it is a copolymer of propylene and an α-olefin having a propylene content of 90 parts by weight or more and a viscosity [η] of 0.1. 70 to 99.5 parts by weight of the component (A) having a MW of 5 to 1.9 dl / g and Mw / Mn of 6 or more, and a propylene polymer having a viscosity [η] of 4.5 to 9 dl / g are used.
A propylene-based polymer consisting of 5 to 30 parts by weight is disclosed. However, in the present invention, the compatibility of the component (A) and the component (B) in the molten state is not sufficient, and the uniformity of the cell film during foam molding is not sufficient. Further, the publication does not show the propylene content of the component (B). Further, the α-olefin content of the component (A) is preferably specified as less than 2 parts by weight, but if it is less than 2 parts by weight, the cushioning property of the foam is insufficient.

[0003] Japanese Patent Application Laid-Open No. 7-252318 discloses that when a single body has a thickness of 20 mm or more, the density is 0.005 to 0.03 g / cm ³ and the average bubble is 0.4 to 0.4 g / cm ³ .
As a polypropylene resin capable of obtaining an extruded foam having 2.0 mm, a closed cell ratio of 80% or more, and a minimum value of maximum acceleration of 80 G or less, a biaxial extensional viscosity at a biaxial extensional strain of 0.2 is obtained. 4.5 × 10 ⁶ Poise or more, 2
The axial strain hardening rate α is 0.30 or more, and the ethylene content is 0.05.
〜8% by weight of a polypropylene-based polymer is disclosed. However, this technique can produce a stable and uniform film up to a certain level, but causes a decrease in film elongation and elongation due to an increase in crystallinity due to crystallization during the growth of a bubble film. Further, the cell membrane buckles when the foam is compressed, which is not preferable. Furthermore, Japanese Patent Publication No. 5-506875 discloses that
By using "polypropylene polymer which is mostly linear but small amount of high molecular weight component is highly branched", sheet-like extrusion of polypropylene polymer having a wall thickness of 0.5 to 5.0 mm There is a statement that a foam is obtained. However, according to this technique, a foam of good quality can be obtained if the thickness is 5 mm or less in the form of a foam sheet. However, in the case of a plate-like foam in which the thickness of the foam is increased to 20 mm or more, foam breakage occurs. There is a problem that the closed cell rate is remarkably reduced.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a single unit having a thickness of 10 mm or more, a closed cell ratio of 80% or more, and a closed cell ratio of 80% after compression. Is 5% or less, and the foam density is 0.009.
It is a propylene-based resin from which an extruded foam of about 0.045 g / cm ³ can be obtained.

[0005]

Means for Solving the Problems The propylene resin of the present invention is characterized by satisfying the following requirements (A) to (E). (A) The ratio σy / between the tensile yield strength σy and the tensile modulus Es
Es is 0.021 or more. (A) The equilibrium compliance Je ₀ at 210 ° C. is 1.
0 × 10 ⁻⁴ or more and 1.2 × 10 ⁻³ (1 / Pa) or less. (C) MFR at 230 ° C. exceeds 0.1 and 10 g / 10
Less than a minute. (D) Zero shear viscosity at 210 ° C. is 0.8 × 10 ⁵ (Pa
・ S) and above. (E) Melting energy ΔH is 55 J / g or more. At this time, it is desirable that the strain hardening temperature range is 4 ° C. or more.

As such a propylene-based resin, 4
It contains the following component (A) of more than 0 and less than 80 parts by weight, and the following component (B) of more than 20 and less than 60 parts by weight.
The propylene-based resin having a ratio [η] _B / [η] _A of intrinsic viscosity [η] (dl / g) of the components (A) and (B) measured in a tetralin solvent of more than 2 and less than 7 desirable. (A) Ingredient: Obtained from more than 93 and less than 98% by weight of propylene and more than 2 and less than 7% by weight of ethylene and / or α-olefin and having an MFR of more than 5 and 50 at 230 ° C.
g / 10 minutes or less of a propylene-based copolymer. Component (B): 93% by weight or more of propylene and 7% by weight
Less than ethylene and / or α-olefin,
A propylene copolymer having an HLMFR at 230 ° C of more than 0.5 and less than 20 g / 10 min, and a zero shear viscosity at 210 ° C of more than 3.0 × 10 ⁵ and less than 9.0 × 10 ⁶ (Pa · s). Coalescing.

Further, a propylene resin characterized by containing 1 to 15 parts by weight of the following component (C) with respect to the above components (A) and (B) is desirable. Component (C): a propylene-based polymer obtained from more than 97% by weight of propylene and less than 3% by weight of ethylene and / or α-olefin and having an MFR of less than 20 g / 10 minutes. Further, ethylene and / or α in component (B) relative to ethylene and / or α-olefin in component (A)
- it is desirable weight ratio C _B / C _A of olefin is less than 1.00.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The propylene resin of the present invention is required to have (a) the ratio σy / Es of tensile yield strength σy to tensile elastic modulus Es of not less than 0.021. In the present invention, the tensile yield strength σy and the tensile modulus E
s is measured by performing a tensile test according to JIS K6758. This tensile yield strength σ
The ratio σy / Es of y to the tensile modulus Es is expressed as “cell structure,
For Use of Porous Materials ”(LJ Gibson, MFAshby
(Translated by Masahisa Otsuka, published in 1993 by Uchida Lao Tsuruga)) is an indicator of the magnitude of recovery after compression deformation. The ratio σy / Es is more preferably 0.023 or more, and further preferably 0.025 or more. If σy / Es is less than 0.021, recoverability after compression tends to be poor. That is, when the foam is compressed, even if the foam is released from the compressive stress, the foam does not return to its original thickness and the cushioning characteristics change. It is considered that this is because the intersection of the ridges formed by the contact of the cell surfaces during compression is deformed, and it is impossible to recover the original cell structure even when the cell is released from the compressive stress. Deformation at the intersection of the ridge lines of the cells causes a large deformation of the cell membrane in the vicinity, resulting in a large decrease in the closed cell rate, resulting in a decrease in the elastic modulus of the foam, a decrease in the yield stress at the time of compression, etc. cause.

In the propylene resin of the present invention,
(A) The equilibrium compliance Je ₀ at 210 ° C. is 1.
It is necessary to be not less than 0 × 10 ^{−4 and not} more than 1.2 × 10 ⁻³ (1 / Pa). The equilibrium compliance Je ₀ is measured by the method described in the section of Examples below, and is a measure of elastic deformation. When the equilibrium compliance Je ₀ is less than 1.0 × 10 ⁻⁴ , bubbles do not grow uniformly, and the closed cell rate decreases. On the other hand, if it is larger than 1.2 × 10 ^-3 , the polypropylene-based polymer becomes “a polypropylene polymer which is mostly linear but a small amount of high molecular weight components are highly branched”. It is speculated that In a polypropylene-based polymer having a structure in which a small amount of a high molecular weight component is highly branched, the thickness of the foam is 2
In the case of a plate-like foam having a thickness of 0 mm or more, there is a problem that foam breakage is remarkably generated, and the closed cell rate is rapidly reduced.

In the propylene resin of the present invention,
(C) MFR at 230 ° C. exceeds 0.1 and 10 g / 10
Must be less than a minute. More preferably more than 0.5 and less than 8 g / 10 min, even more preferably more than 0.5 and 5 g / min.
Less than 10 minutes. If the MFR is less than 0.1 g / 10 minutes, an excessive load is applied to the extruder when the propylene-based resin is melted. If it is 10 g / 10 min or more, the closed cell rate before compression is low, and a thick foam cannot be obtained by extrusion. MF
R is what is called melt flow rate.
7210, which is measured under condition 14 in Table 1.

In the propylene resin of the present invention,
(D) Zero shear viscosity at 210 ° C. is 0.8 × 10 ⁵ (Pa
S) It is necessary to be at least. The zero shear viscosity at 210 ° C. is measured by the method described in the section of Examples described below, and the zero shear viscosity is the value of the ultrahigh molecular weight component when compared with a constant weight average molecular weight. It is a measure of proportion. The zero shear viscosity is 0.8 × 10 ⁵ (Pa · s) or more, and more preferably 3.0 × 10 ⁵ (Pa · s).
It is more preferably at least 5.0 × 10 ⁵ (Pa · s). If it is less than 0.8 × 10 ⁵ (Pa · s), a foam having a high closed cell rate cannot be obtained.

In the propylene resin of the present invention,
(E) The melting energy ΔH needs to be 55 J / g or more. More preferably, it is 60 J / g or more. 55J
If it is less than / g, the rigidity is insufficient. Note that the melting energy Δ
If H is too high, the recovery of the foam after compression is poor, so that the J is 120 J / g or less, preferably 100 J / g or less.
More preferably, it is 90 J / g or less.

[0013] In the propylene resin of the present invention, the strain hardening temperature range is desirably 4 ° C or more. here,
The strain hardening temperature, when the resin is stretched under a certain temperature,
The temperature at which a phenomenon occurs in which the viscosity suddenly increases after elongation to a certain strain occurs, and the difference between the highest temperature and the lowest temperature at which the phenomenon occurs is the strain hardening temperature range. The strain hardening temperature is preferably from 100 to 180 ° C, and from 120 to 170 ° C.
C is more preferred. If it is lower than 100 ° C., it cannot be molded as polypropylene, and if it exceeds 180 ° C., it cannot be molded as polypropylene. Strain hardening temperature range is 4
The temperature is desirably at least 5 ° C, preferably at least 5 ° C. If the temperature is less than 4 ° C., the molding temperature range in which a foam having a high closed cell ratio can be obtained is narrow, and it is difficult to stably obtain a foam having a high closed cell ratio.

As the propylene resin for foaming of the present invention as described above, those containing the following components (A) and (B) are suitable. (A) Ingredient: Obtained from more than 93 and less than 98% by weight of propylene and more than 2 and less than 7% by weight of ethylene and / or α-olefin and having an MFR of more than 5 and 50 at 230 ° C.
g / 10 minutes or less of a propylene-based copolymer. Component (B): 93% by weight or more of propylene and 7% by weight
Less than ethylene and / or α-olefin,
Propylene copolymer having an HLMFR at 230 ° C of 0.5 or more and less than 20 g / 10 min, and a zero shear viscosity at 210 ° C of more than 3.0 × 10 ⁵ and less than 9.0 × 10 ⁶ (Pa · s) .

In the component (A), the MF at 230 ° C.
It is desirable that R is more than 5 and less than 50 g / 10 minutes. If it is less than 5 g / 10 minutes, the fluidity is not sufficient,
If the time is / 10 minutes or more, the swell is small and not sufficient when making a thick plate. In the component (A), 93
From less than 98% by weight of propylene and more than 2 and less than 7% by weight of ethylene and / or α-olefin, preferably more than 94 and less than 96% by weight of propylene and more than 4 and 6% by weight Less than ethylene and / or α
-Obtained from olefins are desirable in terms of preventing foam breakage during molding and reducing a decrease in closed cell ratio when the foam is compressed. When propylene is contained in an amount of 98% by weight or more, the degree of crystallinity is too large, so that the foam film is not stretched during foaming and breaks. If the content is 93% by weight or less, the degree of crystallinity becomes small and the rigidity becomes insufficient. Examples of the α-olefin include 1-butene, 1-pentene, 1-hexene,
-Heptene, 1-octene, 1-decene, 4-methyl-
One example is 1-pentene. These two or more comonomers may be mixed and used for copolymerization with propylene.

The above component (B) has a HLMFR of 230 ° C.
Is more than 0.5 and less than 20 g / 10 min, more preferably more than 4 and less than 10 g / 10 min, even more preferably 4
And less than 8 g / 10 min. If it is less than 0.5 g / 10 minutes, the dispersibility with the component (A) is not sufficient. Also, 20g
If it is longer than / 10 minutes, when forming a thick plate, the pressure at the exit of the forming die is not increased, and it is difficult to make the plate thick. In addition, HLM
FR is what is called high load melt flow rate, JIS K7210, temperature 230 ° C, load 21.6.
It is measured under the condition of kgf. The component (B) is obtained from 93% by weight or more of propylene and less than 7% by weight of ethylene and / or α-olefin,
This is desirable from the viewpoint of maintaining the inherent rigidity of the propylene-based polymer. When the propylene content is less than 93% by weight, the crystallinity becomes small and the rigidity becomes insufficient. 21 of this component (B)
The zero shear viscosity at 0 ° C. exceeds 3.0 × 10 ⁵ and 9.0 ×
It is preferably less than 10 ⁶ (Pa · s), more preferably 5.
More than 0 × 10 ⁵ and less than 3.0 × 10 ⁶ (Pa · s), more preferably more than 5.0 × 10 ⁵ and 1.0 × 10 ⁶ (Pa · s)
s). 3.0 × zero shear viscosity at 210 ° C.
In the case of 10 ⁵ (Pa · s) or less, the viscosity of the cell membrane at the time of foaming is not sufficient, and the membrane breaks. Also, 9.0 × 1
In the case of more than 0 ⁶ (Pa · s), dispersibility with the component (A) is poor. As the α-olefin, similar to the component (A), 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 4-methyl-1-
Penten can be exemplified. These two or more comonomers may be mixed and used for copolymerization with propylene.

In the propylene resin containing the components (A) and (B), the composition ratio of the component (A) is more than 40 and less than 80 parts by weight, preferably more than 50 and less than 70 parts by weight. Is desirable. If it is less than 40 parts by weight, the fluidity is poor. If the amount is more than 80 parts by weight, the closed cell rate will not be sufficiently high. The composition ratio of component (B) is more than 20 and less than 60 parts by weight, preferably more than 30 and 50 parts by weight. If it is more than 60 parts by weight, the fluidity is poor. If it is less than 20 parts by weight, the closed cell rate will not be sufficiently high. Further, the ratio [η] _B of the intrinsic viscosity [η] (dl / g) of the components (A) and (B) measured at 135 ° C. in a tetralin solvent.
/ [Η] _A is more than 2 and less than 7. Preferably, it is more than 2 and less than 6, more preferably more than 2 and less than 5.
When [η] _B / [η] _A is 2 or less, the stability during bubble growth is poor, and the closed cell ratio decreases. If it is 7 or more, the dispersibility of the components (A) and (B) is not sufficient. Further, (A)
In the propylene-based resin containing both the component and the component (B), the propylene content is preferably more than 93 and less than 99% by weight, the ethylene and / or α-olefin content is more than 1 and less than 7% by weight, and More preferably less than 98% by weight and ethylene and / or α-olefin more than 2 and less than 6% by weight, more preferably 9% by weight of propylene.
More preferably, it is more than 5 and less than 97% by weight, and ethylene and / or α-olefin is more than 3 and less than 5% by weight. When the propylene-based resin contains 99% by weight or more of propylene, the closed cell ratio after 80% compression is significantly reduced. If it is less than 93% by weight, the rigidity is insufficient.

By using 1 to 15 parts by weight, preferably 3 to 10 parts by weight of the following component (C) in the resin composition comprising the above components (A) and (B), a foam having a high closed cell rate can be obtained. Can be obtained more stably. The component (C) has an MFR of less than 20 g / 10 min, preferably 15 g / min.
g / 10 minutes or less,
Those obtained from more than 98% by weight of propylene and less than 3% by weight of ethylene and / or α-olefin, preferably propylene obtained from more than 98% by weight of propylene and less than 2% by weight of ethylene and / or α-olefin A polymer is desirable. When the MFR is 20/10 minutes or more, the viscosity of the cell membrane at the time of foaming decreases, and the membrane breaks. Also,
If the content of ethylene and / or α-olefin is 3% by weight or more, no effect is exhibited. When the amount of the component (C) is less than 1 part by weight with respect to the components (A) and (B), it is difficult to stably obtain a foam having a high closed cell ratio, and when the amount exceeds 15 parts by weight, 8%.
After 0% compression, the closed cell rate is significantly reduced.

The propylene resin for foaming of the present invention is obtained by copolymerizing propylene and ethylene or an α-olefin with a Ziegler-Natta catalyst by slurry polymerization or gas phase polymerization or a combination of slurry method and gas phase polymerization. Can be manufactured by When the propylene-based resin is composed of the components (A) and (B) described above, the component (A) is obtained by slurry polymerization or gas phase polymerization, using a Ziegler-Natta catalyst, using hydrogen as a molecular weight controlling agent, and applying a polymerization pressure. By adding 30 to 50 kg / cm ² , a polymerization temperature of 70 to 80 ° C., and 0.5 to 2.0 mol% of ethylene and / or an α-olefin, propylene and ethylene having an MFR of more than 10 and less than 50 g / 10 min. And / or obtain an α-olefin copolymer. The component (B) is prepared by slurry polymerization or gas phase polymerization using a Ziegler-Natta catalyst, hydrogen as a molecular weight controlling agent, a hydrogen concentration of 0 to 0.008 mol%, a polymerization pressure of 30 to 50 kg / cm ² , and polymerization. Temperature 70-80 ° C,
By adding 0.5 to 2.0 mol% of ethylene and / or α-olefin, HLMFR exceeds 0.5 and 20 g / l
A copolymer of propylene with ethylene and / or α-olefin in less than 0 minutes is obtained. The components (A) and (B) can be made into a composition by continuous two-stage polymerization or compounding.

The component (C) is obtained by slurry polymerization or gas phase polymerization using a Ziegler-Natta catalyst, hydrogen as a molecular weight controlling agent, and a polymerization pressure of 30 to 50 kg / cm ² ,
It can be obtained by adding 0 to 2.0 mol of ethylene and / or α-olefin at a polymerization temperature of 70 to 80 ° C. (A),
The components (B) and (C) can be made into a composition by continuous multistage polymerization or compounding.

The method for foaming the propylene resin of the present invention is not particularly limited, and various well-known methods can be applied. For example, a polypropylene is put into an extruder, a resin is melted in the extruder, and a liquefied gas (a volatile foaming agent: for example, a fluorocarbon-based gas, or a hydrocarbon-based gas such as butane or propane) is vaporized under normal temperature and normal pressure in the extruder. Gas) and extrude it (see: JP-A-5-25-2).
No. 28980). This method has the advantage that the resin is cooled by the heat of vaporization of the gas to stabilize the air bubbles and that a foam having a high expansion ratio is easily obtained.
Also, after melting and kneading the polypropylene and the decomposable foaming agent without decomposing the foaming agent and extruding, cross-linking using an electron beam, a cross-linking agent, etc., and heating in a furnace to decompose the foaming agent and foam. Method (Reference: JP-B-46-19854)
There is. According to this method, since the viscosity is increased by the crosslinking, there is an advantage that the expansion ratio is high and a foam having fine cells can be obtained.

Further, a compound (decomposition type foaming agent) which is decomposed by heating to generate a gas together with polypropylene is charged into an extruder, the resin is melted in the extruder, and the foaming agent is heated to a decomposition temperature or higher. Extrusion method (see: Tokubo 5)
8-31098). According to this method, a propylene-based resin may be mixed with a foaming agent using a general blender, a mixer, or the like and charged into an extruder. As a method for continuously and efficiently extruding a foam, a special device is used. The decomposition-type blowing agent generally generates mainly nitrogen and carbon dioxide gas, so there is no need to worry about environmental destruction and ignition, and since it does not require cross-linking, it can be re-melted and recycled. It has the advantage of being possible. There are various types of such thermal decomposition type foaming agents, and examples of organic foaming agents include azodicarbonamide, N, N'-dinitrosopentamethylenetetramine, p, p'-oxybisbenzenesulfonylhydrazide and the like. No. Examples of the inorganic foaming agent include sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, calcium azide and the like. Also, a mixture of an inorganic blowing agent and a fatty acid, such as a mixture of sodium bicarbonate and citric acid, can be used. Among them, an inorganic type such as a mixture of sodium bicarbonate and citric acid is most preferable. The decomposition-type foaming agent preferably has a decomposition temperature of 150 to 210 ° C., but preferably decomposes at the temperature in the extruder.

As a method of molding the foam, a method of extruding a polypropylene-based polymer with an extruder together with a decomposable foaming agent or a volatile foaming agent can be adopted. Melt plasticization by extruder, screw rotation from die head,
A method of extruding and foaming with a plunger, accumulator, etc., or extruding with a foaming nucleating agent such as talc by an extruder, injecting a volatile foaming agent into the molten resin in the extruder, screw rotation from the die head, plan There is a method of extruding and foaming with a jar, an accumulator or the like. During molding, two or more extruders are used to supply the propylene-based polymer of the present invention to one side and a different resin to the other side, and the extruders are supplied to the die head to form a molded body having two or more layers. It is also possible to make.

Examples of the foaming agent include a volatile foaming agent and a decomposition-type foaming agent. Examples of the volatile blowing agent include aliphatic hydrocarbons such as propane, butane, pentane, isobutane, neopentane, isopentane, hexane, and heptane; cycloaliphatic hydrocarbons such as cyclobutane and cyclopentane; methyl chloride, methylene chloride,
Dichlorofluoromethane, chlorotrifluoromethane,
Dichlorodifluoromethane, chlorodifluoromethane,
Difluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, monochloropentafluoroethane, 1,1,1,2-tetrafluoroethane, 1-chloro-1,1-difluoroethane, 1,2-dichloro-
2,2,2-trifluoroethane, 1,1-dichloro-
Halogenated hydrocarbons such as 1-fluoroethane; Examples of the decomposable blowing agent include azodicarbonamide, dinitrosopentamethylenetetramine, azobisisobutyronitrile, sodium carbonate, sodium bicarbonate, potassium bicarbonate, and the like. These foaming agents can be used as a mixture of two or more kinds. The amount of the blowing agent in the present invention varies depending on the type of the blowing agent and the desired expansion ratio, but is generally 0.1 to 30 parts by weight, preferably 0.2 to 20 parts by weight, per 100 parts by weight of the resin. . If the amount is less than 0.1 part by weight, the expansion ratio does not increase, and
If the amount exceeds 0 parts by weight, the resin cannot retain the air bubbles and the air bubbles are crushed, so that the expansion ratio is rather lowered. When an organic foaming agent is used, urea, a fatty acid metal salt, zinc oxide, or the like is used as a foaming aid for adjusting the decomposition temperature to a lower temperature side in an amount of 0.1 to 100 parts by weight of the organic foaming agent.
It can be used by adding 50 parts by weight.

In foaming, talc, fine calcium silicate, aluminum stearate,
Inorganic powders such as calcium carbonate, barium sulfate and silica; acidic salts of polyvalent carboxylic acids; and reactants of polyvalent carboxylic acids and sodium carbonate or sodium bicarbonate may be added in small amounts. Furthermore, lauric amide, myristic amide, palmitic amide, stearic amide, N-methylstearic amide, N-ethylstearic amide, N, N-distearic amide, dilauric amide, distearin Higher aliphatic amides such as acid amide and dipalmitic acid amide;
Dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, eicosylamine, decosylamine, N-methyloctadecylamine, N-ethyloctadecylamine, hexadecylpropyleneamine,
A saturated higher alkylamine such as octadecylpropyleneamine may be blended.

Desired cross-sectional shape according to the intended use;
As a method for molding a foam having a width and a thickness, various methods for obtaining a rod-shaped, sheet-shaped, or board-shaped article using the extruder described above as the foam molding method can be used. A method of obtaining a rod-shaped article using a circular die or a modified die, attaching a T die to an extruder,
A method of extruding into a sheet or board to obtain a foamed sheet, a method of attaching a circular die, extruding into a cylindrical shape, cutting out one or more locations, and obtaining a foamed sheet are suitable. In the method of attaching a circular die, a deformed die, or a T die, extruding into a sheet shape, and obtaining a foamed sheet, a roll provided with a cooling device, a metal plate, It is desirable to control the thickness of the foam sheet coming out of the lip and smooth the surface using a mold or the like. Attach a circular die, extrude it into a cylindrical shape, then cut out one or more places to obtain a foamed sheet.Similarly, in a method of taking out the sheet using a take-up machine, pull out the lip from a lip into a metal cylinder equipped with a cooling device. It is preferable to cover the foamed tubular foam, fix the foam in a sheet while cooling, smooth the surface, and then cut the foam.

The foam provided by the present invention is suitable for use as a cushioning material for packaging of precision equipment, electric products, etc., but is used as a heat insulating material in the construction field, a packaging material for foods, a protective sheet for articles, wall surfaces, etc. It can be used as a core material for bags, stationery, doors, etc. Further, the obtained foamed sheet is softened by heating, and is formed by processing into a container shape by using a mold, and is formed into a food tray, a cardboard box partitioning tray, a bowl,
It can be used as a food container, miscellaneous goods container, parts container, such as a lunch container, a side dish container, a cup, a bowl, a lid, and the like.

In the propylene polymer composition according to the present invention, various additives, compounding agents, fillers and the like can be used as long as the properties of the composition are not impaired. If these are concretely shown, an antioxidant (a heat stabilizer), an ultraviolet absorber (a light stabilizer), an antistatic agent, a protective agent, a flame retardant, a lubricant (a slip agent, an antiblocking agent), a glass filler, etc. Inorganic fillers, organic fillers, reinforcing agents, coloring agents (dyes and pigments), fragrances and the like.

To the propylene resin for foaming of the present invention, a necessary amount of a known nucleating agent may be added for the purpose of rapidly solidifying the propylene resin in the process of solidifying the foam film.
For example, inorganic compounds such as metal salts of carboxylic acids, dibenzylidene sorbitol derivatives, phosphate metal salts, and talc. Specific examples include sodium benzoate, aluminum adipate, sodium thiophenecarboxylate, 1,3,2,4-dibenzylidene sorbitol, 1,3,2,4-di- (p-methylbenzylidene) sorbitol, , 3-p-Chlorobenzylidene-
2,4-p-methylbenzylidenesorbitol, sodium-bis- (4-t-butylphenyl) phosphate, sodium-bis- (4-methylphenyl) phosphate, potassium-bis- (4-t-butylphenyl) Phosphate, sodium-2,2-methylene-
Bis- (4,6-di-t-butylphenyl) phosphate, sodium-2,2'-ethylidene-bis (4,
6-di-t-butylphenyl) phosphate and talc, calcium carbonate and the like. These nucleating agents may be used alone or in combination of two or more.

[0030]

The present invention will be specifically described below with reference to examples. [Example 1] (A) Component Preparation: MgCl ₂ supported TiCl ₄ as catalyst
(Co-catalyst triethylaluminum) with an internal volume of 15
In a 0-liter reactor equipped with a stirrer,
Liter / h, feed ethylene 0.7 mol%, hydrogen concentration 1 mol%, polymerization temperature 75 ° C, polymerization pressure 45 kg /
polymerized in cm ^2, MFR is 45 g / 10 min, ethylene content C _A is obtained by polymerizing a propylene polymer 3.2% by weight. Preparation of component (B): MgCl ₂ supported TiCl ₄ as catalyst
(Co-catalyst triethylaluminum) with an internal volume of 15
In a 0-liter reactor equipped with a stirrer,
Liter / h, feed 0.7 mol% of ethylene, HLMF at a polymerization temperature of 70 ° C., polymerization pressure of 45 kg / cm ² .
R is 1.0 g / 10 min, ethylene content C _B, 3.0%
Was polymerized. (A) prepared above
70% by weight of the component and 30% by weight of the component (B),
With respect to 100 parts by weight of the components (A) and (B), 0.05 parts by weight of an antioxidant (“P-EPQ”), 0.05 parts by weight of calcium stearate, and an antioxidant (Geigy, “ 0.1 parts by weight of Irganox 1010) and a co-rotating twin-screw extruder (KTX3 manufactured by Kobe Steel, Ltd.)
7 mmφ) and melt-kneaded at a die temperature of 220 ° C. to obtain pellets. Various physical properties of the obtained propylene-based resin,
That is, the MFR, ethylene or α-olefin content C
_E, (A) and component (B) ethylene or α- olefin weight percent ratio C _B / C _A, the intrinsic viscosity ratio [η] _B /
Table 1 shows [η] _A , σy / Es, zero shear viscosity η ₀ , equilibrium compliance Je ₀ , and melting energy ΔH.

Example 2 MgCl ₂ supported T as catalyst
Using iCl ₄ (triethylaluminum cocatalyst), in a reactor with an internal volume of 150 liter and equipped with a stirrer, propylene was fed at 60 liter / h and ethylene at 0.8 mol%, and the hydrogen concentration was 0.005 mol% and polymerization was carried out. Polymerization is performed at a temperature of 70 ° C. and a polymerization pressure of 45 kg / cm ² , and the HLMFR is 18 g.
The first stage polymerization was carried out by adjusting the catalyst supply amount so that the ethylene content became 3.8% by weight / 10 minutes. Subsequently, in a reactor with a stirrer having an internal volume of 300 liters, ethylene was fed at 1.0 mol%, and the conditions of a hydrogen concentration of 1 to 2 mol%, a polymerization temperature of 70 ° C., and a polymerization pressure of 45 kg / cm ² were maintained. The amount of the catalyst was adjusted so that the final MFR was 0.8 g / 10 min and the amount of polymerization in the second stage was 50% by weight with respect to the total amount of polymerization. To obtain a propylene-based resin. Table 1 shows properties of the obtained propylene-based resin. The MFR of a propylene-based polymer (corresponding to the component (A)) obtained by performing polymerization under the polymerization conditions of the second step without performing the polymerization of the first step.
Was 28 g / 10 min and [η] _A was 1.2 dl / g.

Examples 3 to 15 and Comparative Examples 1 to 9 Using the same production method as in Example 1, the MFR or HLMFR shown in Tables 1 to 5, ethylene or α-
(A) and (B) having olefin content and composition ratio
The components were prepared. The properties of the components (A) and (B) after compounding are shown in the table.

Comparative Examples 10 to 12 For comparison, various physical properties of each commercially available propylene-based polymer are shown in Table 5. Comparative Example 10 is "PF-815" manufactured by Montell Corporation (formerly Himont, USA) employed in Examples of JP-A-4-363227, and Comparative Example 11 is a polypropylene resin "SG510" manufactured by Japan Polyolefin Co., Ltd. ", Comparative Example 1
2 is a polypropylene resin “SA510” manufactured by Japan Polyolefin Co., Ltd.

Example 16 Preparation of Component (C): MgCl ₂ supported TiCl ₄ as catalyst
(Co-catalyst triethylaluminum) with an internal volume of 15
In a 0-liter reactor equipped with a stirrer,
Liter / h, with a hydrogen concentration of 0.1 mol%, a polymerization temperature of 70 ° C., a polymerization pressure of 45 kg / cm ² and an MFR of 1.3 g.
The propylene-based polymer was polymerized for / 10 minutes. The MFRs shown in Table 3, prepared using the same manufacturing method as in Example 1,
The HLMFR, the component (A), the component (B) and the component (C) having an ethylene or α-olefin content of 55% each.
Table 3 shows the physical properties after compounding in the same manner as in Example 1 for the amount of 36% by weight, 9% by weight, and 9% by weight. [Examples 17 to 20] Using the same manufacturing method as in Examples 1 and 16, the MFR or HLMF shown in Table 3 was used.
The components (A), (B), and (C) having R, the content of ethylene or α-olefin as a component, and the composition ratio (in Example 20, ethylene was fed in a necessary amount) were prepared. The properties of the components (A), (B) and (C) after compounding are shown in the table.

In each table, various physical properties were obtained by the following methods. (MFR) According to JIS K7210, condition 1 in Table 1
4 was measured. (HLMFR) According to JIS K7210, temperature 23
The measurement was performed under the conditions of 0 ° C. and a load of 21.6 kgf. (Ethylene and α-olefin content _CE ) CJ Carman
The method according to ¹³ C-NMR method reported by like was based on (Macromolecules, pp. 10,537 (1977)). In addition, about the value of the component of the second stage obtained by the two-stage polymerization, the value of the component of the first stage, the value of the final propylene-based resin, and the weight fraction of the components of the first and second stages are obtained. It was determined by calculation. (Measurement of intrinsic viscosity [η]) It was measured in tetralin at 135 ° C.

(Zero shear viscosity η ₀ ) Using a propylene-based resin, press-mold at 230 ° C. for 5 minutes at 230 ° C. with a press to prevent bubbles from being formed with a diameter of 25 mm and a thickness of 1.5 mm.
Using a Rheometer (RMS800) manufactured by eometrics, the temperature was 210 ± 1 ° C. and the frequency (ω) was 0.01 rad.
/ Sec to 100 rad / sec, strain 10 to 15%,
The dynamic melt viscosity η ^* was measured using a parallel plate having a diameter of 25 mm arranged with a gap of 1.5 mm ^.
A -ω curve was obtained. The following Büche equation (see: RAFFAELE S
ABIA, Journal of Applied Polymer Science, 7, 3
50 page (1963)), the η ^* -ω curve was fitted by a regression method, and the zero shear viscosity η ₀ was determined by approximation by the least squares method. ln (η ^* / η ₀ ) = (η ^* / η ₀ −C ₁ ) ln (1+ (C ₃ ω) ^C2 )... Bueche's equation Here, C ₁ , C ₂ , and C ₃ are calculated by the regression method. It is a constant determined by

(Measurement of Tensile Yield Strength σy and Tensile Elastic Modulus Es) A tensile test was performed in accordance with JIS K6758, and the tensile yield strength σy and tensile elastic modulus Es were measured. However,
The tensile modulus was measured at a test speed of 50 mm / min. (Equilibrium compliance Je ₀ ) A propylene-based resin was formed into a diameter of 25 mm and a thickness of 1.5 mm by compression at 230 ° C. for 5 minutes by a press so as to prevent bubbles from entering. Rh exam
The test was carried out at a temperature of 210 ± 1 ° C. using a parallel plate with a diameter of 25 mm arranged with a 1.4 mm gap using a Rheometer (RMS800) from eometrics.
The propylene-based resin was creeped for 300 seconds while applying a constant stress of 100 N / m ² . A value obtained by dividing a tangent intercept value (strain value at a time of 0 second) by 100 N / m ² with respect to the obtained creep curve as a contact point at 300 seconds on the horizontal axis was Je ₀ .

(Melt Energy ΔH) ΔH was measured using a differential scanning calorimeter (DSC7 manufactured by Perkin Elmer). Using the heat of fusion of indium of 28.4 J / g, Δ
After performing the calibration of H, an empty aluminum pan is set in the above apparatus, and the temperature is increased from 30 ° C. to 230 ° C. at a rate of 20 ° C./min (primary temperature increase) under a nitrogen atmosphere.
Then, hold for 5 minutes, lower the temperature to 30 ° C. at a rate of 20 ° C./min, hold for 5 minutes, and raise the temperature to a temperature of 230 ° C. at a rate of 20 ° C./min (secondary temperature increase) to obtain a baseline correction curve. Was. About 5 mg of the propylene-based resin was measured under the same conditions as above, and a melting curve was obtained. Baseline correction was performed on the secondary heating melting curve to obtain ΔH.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

[Table 4]

[0043]

[Table 5]

Each of the propylene resins of Examples 1 to 20 and Comparative Examples 1 to 12 was foamed to produce a propylene foam. For molding, an extruder in which a first extruder (diameter 40 mm, L / D = 32) having a foaming agent injection port in a cylinder and a second extruder (diameter 60 mm, L / D = 28) were used. . As a foaming agent, a mixed Freon gas containing 60% by weight of HCFC142b and 40% by weight of HCFC22 was used. The resin temperature was raised to the melting point or higher by the first extruder to melt the resin, the foaming agent was injected, the resin temperature was lowered to the appropriate foaming temperature by the second extruder, and then extruded through a 3 mmφ circular die to foam. Adjust the resin discharge rate to 4kg / h,
The injection amount of the blowing agent was adjusted to 0.6 kg / h. The measurement results of the foaming temperature width during foam molding, the foam density of each obtained propylene-based foam, the closed cell ratio before and after 80% compression, and the foam thickness were measured using the propylene-based resin as a barrel pressure (capillary) in a capillary. Pressure ΔP),
Table 6 along with the measurement results of strain hardening temperature width and stiffness
-8.

(Method of measuring closed cell rate) ASTM D2
The actual volume V of the sample was measured using an air-comparison hydrometer (“1000” manufactured by Tokyo Science Co., Ltd.) in accordance with 856.
a was measured to determine a closed cell rate. The closed cell ratio is a ratio of closed cells to all cells. Closed cell rate Fc
(%) Is obtained by the following equation. In addition, the closed cell ratio is the rod-shaped foam sample as obtained (before 80% compression)
And a sample in which the rod-shaped foam sample was radially compressed to a diameter of 20% of the original diameter (after 80% compression). Fc = 100−Fo−Fw Fo = {(Va−Vx) / Va} × 100 Fw = (Vw / Va) × 100 Va = 1 × h × w Vw = W / ρr where Fo: open cell rate ( %) Fw: Volume fraction occupied by the bubble wall (%) Va: Apparent volume of sample Vx: Actual volume of sample Vw: Volume of bubble wall l: Length of sample h: Height of sample w: Width of sample W : Weight of sample ρr: Specific gravity of resin

(Measurement of Capillary Pressure ΔP) It is measured using a Capillograph 1C manufactured by Toyo Seiki Seisaku-sho. As measurement conditions, about 10 to 20 g of propylene-based resin was charged into a barrel whose temperature was adjusted to 190 ° C. using a capillary having a diameter of 0.76 mm, a length of 0.76 mm, and an incident angle of 30 °, and air was blown with a metal rod. The resin is driven out until the volume of the molten resin becomes 50% or more of the barrel volume. Thereafter, when the resin is melted, the resin is extruded from the capillary at a constant speed (0.5, 7.5, 10, 20, 30 mm / min) at a constant speed, and the stress in the barrel at a shear rate of 650 sec ^-1 is measured. And defined as ΔP. (Measurement of Stiffness) The press pieces obtained according to JIS K6758 were measured according to ASTM D747-70.

(Measurement of strain hardening temperature)
After compression-molding into a flat plate having a thickness of about mm, cut out to a width of about 6.5 mm and a length of about 80 mm, measure the width and thickness accurately using a caliper and a thickness gauge, and then measure the elongational viscosity (RME: Rheo).
metric Scientific). After the temperature in the device was stabilized at a constant temperature, the device was stretched at a strain rate of 0.1 / sec, and a force suspended by the stretching (hereinafter, referred to as tension) was measured.
The same measurement was performed while changing the measurement temperature. When measured at a certain temperature, a phenomenon in which the tension suddenly increases after the sample has been stretched to a certain extent is observed.If the measured temperature is lower than such a temperature range, the sample is in a solid state, so the tension is increased together with the extension. Rapidly rises, and when the measurement temperature is high, the tension gradually decreases with elongation due to the molten state. Here, under the above measurement conditions, the melt tension is plotted against the true strain ε, the true strain can be extended without cutting to 2 or more, and the melt tension becomes a constant value when the true strain is 1 or more, or After the decrease, it may rise again. The temperature was measured while changing the measurement temperature by 1 ° C., and the temperature at which the above phenomenon occurred was defined as the strain hardening temperature, and the difference between the maximum value and the minimum value was defined as the strain hardening temperature width. FIG. 1 shows a graph of melt tension versus true strain ε for the propylene-based resin of Example 14. The true strain ε is given by the following equation. ε = ln (l ₁ / l ₀ ) where l ₁ is the length of the expanded sample, and l ₀ is the initial length of the sample.

(Foaming Molding Temperature Range) The resin temperature range immediately before extrusion to obtain a foam in a good state was defined as a foaming molding temperature range. In order to measure this temperature range, when foam molding was performed under the above foam molding conditions, molding was performed by changing the temperature of the extruded resin by changing the cylinder temperature and the die temperature of the second extruder. The resin temperature was measured using a thermometer using a thermocouple, and a probe was inserted to measure the resin temperature at a location about 10 mm into the extruder side from the die outlet. When the resin temperature is low, the resin in the semi-solidified state is mixed with the foam, and the foamed state becomes uneven. The temperature at which this state was observed was defined as the lower limit of the foam molding temperature. In addition, when the resin temperature increases, a good foam can be obtained because the foam structure cannot be maintained after extrusion due to a decrease in viscosity, or the foaming agent is vaporized in the extruder and separated from the resin due to a decrease in pressure. Can not be. The temperature at which this state was observed was taken as the upper limit of the foam molding temperature. The foam molding temperature range was a numerical value obtained by subtracting the lower limit temperature from the upper limit of the foam molding temperature.

[0049]

[Table 6]

[0050]

[Table 7]

[0051]

[Table 8]

As is clear from Tables 6 to 8, when the foam of the example was used, the thickness of the foam alone was 15 mm or more, the closed cell ratio was 80% or more, and the closed cell ratio after 80% compression was reduced. It is 75% or more within 4% and the density of the foam is 0.030 g / cm ³ or less, which is a very light extruded foam.

[0053]

The propylene-based resin of the present invention has high mechanical properties, a high closed cell ratio, a high expansion ratio, and a high buffering property. In addition, it is possible to obtain a uniform foam, and it is hard to buckle even when compressed. In addition, a molded article having a large wall thickness can be obtained without foaming. Further, in the propylene resin of the present invention, the (A)
The compatibility between the component and the component (B) in the molten state is good, and a foam having uniformity and excellent buffering properties can be obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the true strain ε and the melt tension for each temperature in Example 14.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takamasa Tsuyuki 2nd Nakanosu, Oita-shi, Oita Japan Polyolefin Co., Ltd. Polyolefin Co., Ltd.

Claims (5)

[Claims] 1. A propylene-based resin which satisfies the following requirements (A) to (E). (A) The ratio σy / between the tensile yield strength σy and the tensile modulus Es
Es is 0.021 or more. (A) The equilibrium compliance Je ₀ at 210 ° C. is 1.
0 × 10 ⁻⁴ or more and 1.2 × 10 ⁻³ (1 / Pa) or less. (C) MFR at 230 ° C. exceeds 0.1 and 10 g / 10
Less than a minute. (D) Zero shear viscosity at 210 ° C. is 0.8 × 10 ⁵ (Pa
・ S) and above. (E) Melting energy ΔH is 55 J / g or more. 2. The propylene resin according to claim 1, wherein the strain hardening temperature range is 4 ° C. or more. 3. The following (A) of more than 40 and less than 80 parts by weight:
A ratio of the intrinsic viscosity [η] (dl / g) of the components (A) and (B) measured at 135 ° C. in a tetralin solvent, containing the following component (B) exceeding 20 and less than 60 parts by weight [ η]
3. The propylene resin according to claim 1, wherein _B / [η] _A is more than 2 and less than 7. (A) Ingredient: Obtained from more than 93 and less than 98% by weight of propylene and more than 2 and less than 7% by weight of ethylene and / or α-olefin and having an MFR of more than 5 and 50 at 230 ° C.
g / 10 minutes or less of a propylene-based copolymer. Component (B): 93% by weight or more of propylene and 7% by weight
Less than ethylene and / or α-olefin,
A propylene copolymer having an HLMFR at 230 ° C of more than 0.5 and less than 20 g / 10 min, and a zero shear viscosity at 210 ° C of more than 3.0 × 10 ⁵ and less than 9.0 × 10 ⁶ (Pa · s). Coalescing. 4. The propylene-based resin according to claim 3, wherein the propylene resin contains 1 to 15 parts by weight of the following component (C) with respect to the components (A) and (B). Component (C): a propylene-based polymer obtained from more than 97% by weight of propylene and less than 3% by weight of ethylene and / or α-olefin and having an MFR of less than 20 g / 10 minutes. 5. Ethylene and / or α in component (B) relative to ethylene and / or α-olefin in component (A)
- claim 3 or 4 propylene resin, wherein the weight ratio C _B / C _A olefins and less than 1.00.