JP2003253065A - Propylene resin composition for foaming, foamed sheet and manufacturing process therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a resin for foaming which yields a foamed sheet showing excellent productivity and smoothness, to provide a foamed sheet showing excellent productivity and smoothness and a manufacturing process therefor. <P>SOLUTION: The propylene resin composition for foaming contains a crystalline propylene polymer (a) having an intrinsic viscosity of ≥7 dl/g. The composition has a shear viscosity of 50-85 Pa.s determined at 185°C at a shear rate of 2,432/s and a shear viscosity of 40-65 Pa.s determined at 185°C at a shear rate of 3,648/s. In the process for manufacturing the foamed sheet, a foaming agent is mixed with the molten propylene resin composition, extruded from a die, cooled and solidified. The foamed sheet comprising the propylene resin composition obtained through this process has an expansion ratio of 1.5-5 and a thickness of 1-7 mm. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a propylene resin composition for foaming, a method for producing a foamed sheet using the same, and a foamed sheet comprising the same.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 11-228629 discloses that
A method for producing a propylene-based resin containing a small amount of a crystalline propylene polymer having a high intrinsic viscosity by a multi-stage polymerization method, and that the propylene-based resin is suitable for producing an extrusion foam molded article having a high expansion ratio is disclosed. ing.

[0003]

The propylene-based resin and the resin composition containing the propylene-based resin can be extruded and foamed to obtain a sheet having a high expansion ratio. It has been found that when extrusion foam molding is performed at high speed in order to realize high productivity in accordance with the above, unevenness of tens of mm span is generated on the surface of the obtained foam sheet, and smoothness may be lost. The purpose of the present invention is to
It is an object of the present invention to provide a resin for foam molding which gives a foamed sheet excellent in productivity and smoothness, a foamed sheet excellent in productivity and smoothness, and a method for producing the foamed sheet.

[0004]

The present invention has an intrinsic viscosity of 7
A propylene-based resin composition for foam molding containing a crystalline propylene polymer (a) of dl / g or more at a temperature of 1
The shear viscosity at 85 ° C and a shear rate of 2432 / s is 50 to 85 Pa · s, and the shear viscosity at a temperature of 185 ° C and a shear rate of 3648 / s is 40 to 65 Pa · s.
The propylene-based resin composition for foam molding, and the method for producing a foamed sheet in which the foaming agent and the molten propylene-based resin composition for foam molding are mixed, extruded from a die, and solidified by cooling. Further, the present invention comprises a foamed sheet obtained by the production method, and the propylene resin composition for foam molding, and has a foaming ratio of 1.
The foamed sheet has a thickness of 5 to 5 times and a thickness of 1 to 7 mm. Hereinafter, the present invention will be described in more detail.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The propylene-based resin composition for foam molding of the present invention contains a crystalline propylene polymer (a) having an intrinsic viscosity ([η] a) of 7 dl / g or more, and has a melt strength and a foaming property. It has excellent properties. That is, the intrinsic viscosity [η] a is 7
It is preferably higher than dl / g, and there is no particular upper limit, but it is usually lower than 15 dl / g. More preferably 7
~ 11 dl / g.

In JP-A-11-228629, the relationship between the intrinsic viscosity of the similar component (a) and the content of the component (a) in the propylene-based polymer is improved by satisfying the formula (2). It is said that the effect is large and preferable, and when importance is attached to fluidity, it is preferable that the content of the component (a) is smaller as long as the formula 2 is satisfied. Content (% by weight) of component (a) ≧ 400 × EXP (−0.6 × intrinsic viscosity (dl / g) of component (a)) ... <Formula 2> The present inventors ] Regarding a and content Wa,
As a result of earnest studies from the viewpoints of melt strength, foamability, productivity, and smoothness, it was found that suitable conditions exist even if the content is lower than the term on the right side of Formula 2. That is, the content Wa
Is preferably in the range shown in Formula 1. 600 × EXP (−0.6 × [η] a) ≧ Wa ≧ 100 × EXP (−0.6 × [η] a) ... <Formula 1> (where [η] a is the crystallinity) The intrinsic viscosity (unit: dl / g) of the propylene polymer (a) is represented, and Wa represents the content (unit: weight%) of the crystalline propylene polymer (a).)

If the content Wa is too small, it is difficult to obtain the effect of improving the melt strength and foamability. Further, if the content Wa is too large, it is difficult to obtain the balance between productivity and smoothness, which is the object of the present invention. Since (a) is a high-molecular weight component, if it is contained in an excessively large amount, fluidity is likely to be impaired, and melt fracture tends to occur. Content W
The range of a is preferably the above range, more preferably the range of Formula 3, and further preferably the range of Formula 4. 400 × EXP (−0.6 × [η] a)> Wa ≧ 100 × EXP (−0.6 × [η] a) <Equation 3> 300 × EXP (−0.6 × [η]) a) ≧ Wa ≧ 150 × EXP (−0.6 × [η] a) ... <Formula 4>

The propylene resin composition for foam molding of the present invention is a resin composition having a low shear viscosity at a high shear rate and a high fluidity, and the temperature of the entire propylene resin composition for foam molding of the present invention is 185 ° C. , Shear rate 2432
Shear viscosity at 50 / s is 50 to 85 Pa · s,
The shear viscosity at a temperature of 185 ° C. and a shear rate of 3648 / s is 40 to 65 Pa · s. The measurement temperature is 18
5 ° C is a value close to the resin temperature at the die exit at the time of actual extrusion foam molding, and is 2432 / s or 364 which is the shear rate.
8 / s is also a value close to the target production rate. The shear viscosity under these conditions can be easily obtained by the measuring method described in the examples.

Shear rates 2432 / s and 3648 /
If the shear viscosity in s is too high, the uneven swell due to the melt fracture becomes large. Further, when the shear viscosity at the shear rates of 2432 / s and 3648 / s is too low, uneven swelling is small, which is preferable, but foaming is promoted in the die and the foam is easily broken. The shear viscosity at a shear rate of 2432 / s is preferably 60 to 80 Pa · s, and the shear viscosity at a shear rate of 3648 / s is preferably 50 to 65 Pa · s.

The propylene-based resin composition for foam molding of the present invention has a high fluidity at a high shear rate and generally has a high flexural modulus but a low impact strength. The propylene-based resin composition for foam molding of the present invention contains an amorphous ethylene / α-olefin copolymer (b) or a crystalline ethylene / α-olefin copolymer (c) in addition to the above. ) Is preferable because it has an excellent balance between productivity and impact strength. More preferably, both the component (b) and the component (c) are contained.

The composition ratio of the amorphous ethylene / α-olefin copolymer (b) is not particularly limited as long as it is essentially amorphous, but the content of repeating units derived from ethylene is not limited. , 10 to 50% by weight is mentioned as a preferable range. Examples of the α-olefin include propylene, 1-butene, 4-methyl-1-pentene, 1-octene and 1-hexene, but are not particularly limited thereto.

The crystalline ethylene / α-olefin copolymer (c) preferably has a density of 0.86 to 0.91.
g / cc, MFR (190 ° C, 21.18N) 1-3
It is a copolymer of 0 g / 10 minutes. If the density is too low, the impact improving effect is good, but the flexural modulus of the foamed sheet is greatly reduced, and the heat resistance of the foamed sheet is also reduced, which is not preferable. If the density is too high, the impact improving effect is lowered, which is not preferable. More preferably density 0.86-0.88g
/ Cc. If the MFR is too low, it is difficult to adjust the fluidity of the entire composition to a high level, and if the MFR is too high, the impact improving effect is difficult to obtain. More preferably 2 to 20
g / 10 minutes, more preferably 2 to 10 g / 10 minutes. Examples of the α-olefin include propylene, 1-butene, 4-methyl-1-pentene, 1-octene and 1-hexene, and the content of the repeating unit derived from the α-olefin is preferably 5 to 40. % By weight. Among the α-olefins, 1-octene is particularly preferable.

If the content of the amorphous ethylene / α-olefin copolymer (b) is too small, the effect of improving the impact strength will be low, and if it is too large, the flexural modulus will decrease. 10 to 30% by weight of the whole resin component is preferable,
More preferably 10 to 25% by weight, still more preferably 1
It is 0 to 20% by weight.

If the content of the crystalline ethylene / α-olefin copolymer (c) is too small, the effect of improving the impact strength is low, and if it is too large, the flexural modulus decreases, so the content is too small. Is preferably 5 to 30% by weight, more preferably 5 to 25% by weight, and further preferably 5 to 20% by weight based on the entire resin component.

The resin component contained in the propylene resin composition of the present invention other than the above is usually a propylene resin. The propylene-based resin is an ordinary Ziegler-Natta type catalyst, homopolymerized with propylene, or a sufficient amount of ethylene and / or α-olefin having 4 to 12 carbon atoms so as not to lose crystallinity. It refers to a polymer obtained by copolymerizing the comonomer and propylene. The polymer thus obtained is usually linear without branching. By selecting an appropriate propylene-based resin, the shear viscosity of the entire resin composition may be adjusted to fall within the above range. For such preparation, a propylene-based resin having an MFR (230 ° C., 21.18N) of 100 to 1000 g / 10 min is preferably used. The propylene-based resin may be a single resin, but may be a mixture of two or more kinds, and is a polymer that is polymerized and manufactured in a series of manufacturing processes at the time of manufacturing the components (a) and (b). May be.

Since the component (a) is a high molecular weight component, it is preferably used by being produced together with other resin components in a series of production processes from the viewpoint of dispersibility and the like. The propylene polymer (T) shown below is preferable as the resin containing the component (a). That is, the intrinsic viscosity is 7 dl / g
Obtained by a polymerization method including the steps of producing the crystalline propylene polymer portion (A) and the step of producing the crystalline propylene polymer portion (B) having an intrinsic viscosity of less than 3 dl / g, and an intrinsic viscosity of 3 dl / g. and the content of the crystalline propylene polymer portion (A) is less than 0.05% by weight.
It is the propylene polymer (T) of not less than 35% by weight.

The propylene polymer (T) is a polymer obtained by a polymerization method including a step of producing (A) and a step of producing (B). For example, a batch polymerization method in which (A) is polymerized in the first stage and then (B) is polymerized in the same polymerization tank as that in which the (A) is polymerized in the second stage, or two or more polymerization tanks are used. It is obtained by a method such as a continuous polymerization method in which the products are arranged in series and after the polymerization of (A) as the first step, the product is transferred to the next polymerization tank and (B) is polymerized as the second step in the polymerization tank. It is a polymer. In the case of the continuous polymerization method, each of the first stage and second stage polymerization tanks may be one tank or two or more tanks.

The content of the crystalline propylene polymer portion (A) in the propylene polymer (T) is preferably 0.05% by weight or more, more preferably 0.3% by weight or more, from the viewpoint of melt strength. From the viewpoint of elongation properties, the amount of the crystalline propylene polymer portion (A) is preferably as small as possible as long as it has sufficient melt strength to obtain a foam, and usually 35.
It is preferably less than 20% by weight, more preferably 20% by weight or less. The proportion of (A) may be adjusted to a predetermined amount during the polymerization, depending on the polymerization conditions.

From the viewpoint of fluidity and processability, the intrinsic viscosity of (B) is preferably less than 3 dl / g, and from the viewpoint of fluidity and processability, the intrinsic viscosity of the whole propylene polymer (T) is also 3 dl / g. It is preferably less than. MFR of the entire propylene polymer (T) (230 ° C, 21.18N)
Is preferably in the range of 5 g / 10 minutes or more and 30 g / 10 minutes or less. If the MFR is too high, the melt tension required for foaming cannot be maintained, and if it is too low, the workability is affected, specifically, heat generation due to shearing and the resin temperature increase are large. The MFR
The lower limit is more preferably 8 g / 10 minutes or more, and further preferably 10 g / 10 minutes or more. The upper limit of the MFR is more preferably 25 g / 10 minutes or less, further preferably 20 g / 10 minutes or less. From the viewpoint of the appearance of the foamed sheet, the molecular weight distribution of the entire propylene polymer (T) is preferably 15 or less, more preferably 5 or more and 12 or less, and still more preferably 6 or more and less than 10. The molecular weight distribution as used in the present invention is the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn).
Evaluate with.

In the case of continuous polymerization, the intrinsic viscosity of (B) can be set within the above range by appropriately setting the production conditions of (B). In the case of a propylene polymer (T) composed of (A) and (B), assuming that the additivity of the intrinsic viscosity usually holds, the intrinsic viscosity [η] _{T of} the propylene polymer (T) finally obtained And (A) intrinsic viscosity [η]
The intrinsic viscosity of (B) is calculated from the contents (% by weight) of _A and (A) and (B) in (T) by the following mathematical formula 2. _{[Η] B = ([η} ] T × 100- [η] A × W A) ÷ W B [ Equation 2] [η] _T: the intrinsic viscosity of propylene polymer (T) (dl /
g) [η] _A: intrinsic viscosity (dl / g) W _A crystalline propylene polymer portion (A): The content of the crystalline propylene polymer portion (A) (wt%) W _B: crystalline propylene heavy Content of combined part (B) (% by weight)

Each of (A) and (B) is a crystalline propylene polymer portion having a polypropylene crystal structure, and is a homopolymer of propylene or propylene,
Ethylene and / or α in an amount that does not cause loss of crystallinity
-Copolymers with comonomers such as olefins are preferred.
Examples of the α-olefin include 1-butene, 4-methyl-1-pentene, 1-octene, 1-hexene and the like. The amount that does not lose crystallinity depends on the type of comonomer, but in the case of ethylene, the amount of ethylene units in the copolymer is usually 10% by weight or less, and in the case of other α-olefins such as 1-butene. , Α- in the copolymer
The amount of olefin units is usually 30% by weight or less.
(A) and (B) may have the same composition or different compositions. Further, (A) and (B) may be connected in a block manner. Further, (A) and (B) are block-bonded and other (A) and (B)
And may coexist.

In addition to the above, (B) can also be exemplified by a polymer in which an amorphous ethylene / α-olefin copolymer is dispersed in a crystalline propylene polymer (T).

The propylene polymer (T) is, for example,
It can be produced by using a solid catalyst containing a Ti atom, a Mg atom, and a halogen atom.
The method described in JP-A-228629 can be mentioned.

Since the component (b) is amorphous, it is preferable to use one produced in a series of production processes together with other resin components in view of handling problems and the like. As the resin containing the component (b), a propylene-ethylene block copolymer (S) obtained in the following first step and second step is preferable. First step: homopolymerization of propylene, or until the polymer portion (C) having a content of repeating units derived from ethylene of 0 to 2% by weight becomes 70 to 90% by weight of the total amount of copolymer, or A step of copolymerizing propylene and ethylene. Second step: In the presence of the polymer portion (C) obtained in the first step, the polymer portion (D) having a content of repeating units derived from ethylene of 10 to 50% by weight is used as propylene. The process of producing by copolymerizing with ethylene.

Since many commercially available products are sold as those which correspond to the component (c), they may be appropriately selected and used.

In a preferred embodiment of the propylene resin composition for foam molding of the present invention, the content of the component corresponding to the crystalline propylene polymer (a) having an intrinsic viscosity of 7 dl / g or more satisfies the formula 1. The crystalline ethylene / α-olefin copolymer (c) containing the propylene polymer (T), the amorphous ethylene / α-olefin copolymer (b) in an amount of 10 to 30% by weight. 5% to 30% by weight, and MFR (230 ° C., 21.
18N) is a composition containing a propylene-based resin of 100 to 1000 g / 10 min. In addition, all the contents mentioned here are expressed as a weight percentage with respect to the whole resin component in the composition. 600 × EXP (−0.6 × [η] a) ≧ Wa ≧ 100 × EXP (−0.6 × [η] a) ... <Formula 1> (where [η] a is the crystallinity) The intrinsic viscosity (unit: dl / g) of the propylene polymer (a) is represented, and Wa represents the content (unit: weight%) of the crystalline propylene polymer (a).)

A foamed sheet is obtained by melting the propylene-based resin composition for foam molding of the present invention, mixing it with a foaming agent, extruding it from a die, and solidifying by cooling. The foaming agent used in the present invention is not particularly limited, and as the physical foaming agent, carbon dioxide gas, nitrogen gas, air, propane,
Butane, pentane, hexane, dichloroethane, dichlorodifluoromethane, dichloromonofluoromethane, trichloromonofluoromethane, etc. can be used alone or in combination, but is preferably a safe and environmentally friendly inorganic substance such as nitrogen gas, carbon dioxide gas, air, etc. Gas, and most preferably carbon dioxide. Carbon dioxide is preferable because it has a relatively high solubility in propylene-based resin among inorganic gases.
Carbon dioxide gas is in a supercritical state at 7.4 MPa or higher and 31 ° C. or higher, and has excellent diffusion and solubility in the resin.

Examples of the chemical foaming agent include baking soda, a mixture of baking soda and an organic acid such as citric acid, sodium citrate and stearic acid, an isocyanate compound such as azodicarboxylic acid amide, tolylene diisocyanate and 4,4'diphenylmethane diisocyanate. Azobisbutyronitrile, barium azodicarboxylate, diazoaminobenzene, azo such as trihydrazinotriazine, diazo compounds, benzenesulfonyl hydrazide, P,
P'-oxybis (benzenesulfonyl hydrazide), hydrazine derivatives such as toluene sulfonyl hydrazide, N, N'-dinitroso pentamethylene
Nitroso compounds such as tetramine, N, N'-dimethyl-N, N'-dinitroso terephthalamide, semicarbazide compounds such as P-toluene sulfonyl semicarbazide and 4,4'oxybisbenzenesulfonyl semicarbazide, as well as azides and triazoles The compounds and the like are used alone or in combination, and sodium bicarbonate, citric acid or azodicarboxylic acid amide is particularly preferably used.

These physical foaming agents and chemical foaming agents may be used alone, but they may be used in combination. Further, in the use of these chemical foaming agents, a foaming aid may be used in combination in order to adjust the decomposition temperature and rate. For example, azodicarboxylic acid amide alone has a high decomposition temperature of about 200 ° C., and if it is desired to process at a low temperature, a small amount of zinc oxide, zinc stearate, urea or the like may be added as a foaming aid. In the case of physical foaming, in particular, a bubble nucleating agent is often added, but as the nucleating agent, talc, silica, diatomaceous earth,
Calcium carbonate, magnesium carbonate, barium sulfate, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, calcium silicate, zeolite, mica, clay, wollastonite, hydrotalcite, magnesium oxide, zinc oxide, zinc stearate, steer A small amount of calcium phosphate, polymer beads such as PMMA, synthetic aluminosilicate or the above-mentioned chemical foaming agent may be added.

In the present invention, usually, a resin and a foaming agent are melt-kneaded by using an extruder or the like, and extruded into the atmosphere through a die connected to the extruder. INDUSTRIAL APPLICABILITY The present invention is preferably applied to a method using a T-die as a die. A flat molten sheet obtained by using a T-die is brought into contact with a large number of rolls which are placed immediately after the die and whose cooling temperature is controlled, or between two cooling plates whose cooling temperature is controlled. After cold-molding the sheet by a known cold-molding method such as passing it while allowing it to be taken by a take-off machine provided with a nip roll,
A foaming sheet is manufactured by cutting into a predetermined size with a cutting machine.

Examples of such an extruder include a single-screw extruder and a multi-screw extruder, and a tandem extruder in which a plurality of these extruders are combined can also be used. Especially single screw extruder, 2
A shaft extruder is preferable, and a structure in which the amount of extrusion per screw rotation is large and a predetermined amount of extrusion can be obtained at low rotation and shear heat generation due to screw rotation is small is preferable. Also, circulate the cooling medium in the screw body,
You may adjust the temperature. Further, a gear pump is provided between the extruder and the die, and a quantitative feeder is provided for supplying the raw material to control the inlet pressure of the gear pump at a constant level. Therefore, a control system that feeds back to the screw rotation speed and the raw material supply amount is also effective. Furthermore, it is also effective to insert a static mixer or the like into the adapter that connects the extruder and the die to make the resin temperature uniform. In the case of physical foaming, the extruder for foaming has a structure that allows the foaming agent to be press-fitted midway, but before the press-fitting position, the resin raw material is sufficiently melted and plasticized, and after press-fitting, the resin and foaming agent are thoroughly mixed and homogenized. Therefore, it is necessary to control the resin temperature suitable for foaming.

The flow path structure of the T-die is not particularly limited, but a structure having a manifold of the coat hanger and a choke bar for adjusting the thickness in the width direction is preferable. A structure that can maintain high resin pressure up to the lip tip is preferable,
The length of the lip land is preferably 0 to 10 mm, more preferably 0 to 5 mm. Shorter lip lands are preferable because they can easily reduce uneven swelling due to melt fracture.

Further, a surface treatment such as corona treatment, ozone treatment or application of an antistatic agent, which is usually applied to the surface of the propylene-based resin foamed sheet, can be performed.

The foamed sheet obtained using the propylene resin composition for foam molding of the present invention has a smooth surface and a high expansion ratio even when processed at high speed. The shape of the foamed sheet in the present invention, such as the foaming ratio and thickness, varies depending on various conditions such as the die width used, lip opening, resin composition, foaming agent, and take-up molding conditions, but the foaming ratio is usually 1.5 to 5. Double, the thickness is in the range of 1 to 7 mm.

The foamed sheet of the present invention is recyclable. As a recycling method, the obtained foamed sheet is crushed by a crusher, and if necessary, the crushed product is degassed by an extruder, regenerated into pellets, and used. In particular, the propylene-based resin composition for foam molding of the present invention has little deterioration in its foamability and mechanical properties even when it is repeatedly extrusion foam-molded, and can be made of 100% recycled material depending on the expansion ratio and thickness.

The foamed sheet obtained in the present invention may be laminated with a skin material such as a sheet or film according to the intended use,
It is also possible to subject these laminated skin foam sheets to thermoforming such as vacuum forming. As a skin material such as a laminated sheet or film, a known material can be used according to the application, and examples thereof include a thin metal plate such as aluminum or iron, a thermoplastic resin sheet, a thermoplastic resin film, or a thermoplastic resin additive. Examples include decorative sheets, thermoplastic resin decorative films, thermoplastic resin foamed sheets, papers, synthetic papers, non-woven fabrics, woven fabrics, hemp, glass wool and carpets.

For example, for food use, 10 to 100
A propylene-based resin film or a gas barrier resin film having a thickness of μm is often attached. As a barrier resin,
EVOH (ethylene / vinyl alcohol copolymer), P
VDC (polyvinylidene chloride), PVA (polyvinyl alcohol), PA (polyamide), etc. can be used. These gas barrier resins may be used alone or in combination, or two or more films of a single film may be used.
You may stack and use.

For automobile interior materials, non-woven fabrics, woven fabrics, hemp, glass wool, carpets and the like are often laminated. In addition, for use in packaging, for example, when used as a partition plate of a box, a buffer sheet such as a high-magnification foam sheet may be attached to protect the contents.

The method for laminating the skin material is not particularly limited. For example, a method in which an adhesive is applied to the surface of the foamed sheet for laminating, a sheet or film laminated with an adhesive resin film is used, and the adhesion is performed. A method of heating and melting the resin film surface to bond with the foam, a method of directly melting the surfaces of each other with a heater or hot air without using an adhesive or an adhesive resin film, and bonding the molten resin. Examples include a method of extruding and laminating between a skin material and a foam sheet, and laminating.

Examples of thermoforming include vacuum forming and hot ruled line processing, but are not particularly limited. Since the foamed sheet of the present invention has good smoothness and fine bubbles, it has excellent thermoformability.

[0041]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples unless the gist thereof is impaired. The evaluation methods used in Examples and Comparative Examples are shown below.

(1) [η] a and Wa: Intrinsic viscosity [η] _A and content W _A were determined by the method already described. [Η] a in this example is the same as [η] _A , and Wa was calculated from the amount ratio of each resin component used and W _A.

(2) Shear viscosity: Using a capillary rheometer manufactured by Toyo Seiki Co., Ltd., sample amount 15 g, preheating temperature 185 ° C., preheating time 10 minutes, barrel diameter 9.55 m
m, piston speed 200 mm / min (shear speed 2432
/ S) and 300 mm / min (3648 / s), the strand was extruded from an orifice having a length of 40 mm and a diameter of 1 mm, and the shear viscosity was measured.

(3) Shear rate at the lip portion: Calculated by the equation 5 by setting the density of the molten resin to 0.75 g / cc. Shear rate = 6 V / Wd ² <Equation 5> V = E × 1000 / (60 × 60 × 0.75) E: Extrusion amount (unit: kg / hr) W: Die width (unit: cm) d : Lip gap (unit: cm)

(4) Foaming ratio: According to JIS K7112, the density ρf of the foamed body was obtained by using the measuring method by the underwater substitution method. The expansion ratio is the density ρs of the unfoamed thermoplastic resin divided by ρf. In the embodiment, ρs = 0.
The expansion ratio was calculated as 9 g / cc.

(5) Flexural Modulus: Using a test device specified in JIS K7203, 50 × 100 mm test pieces in MD and TD were measured at a bending speed of 10 mm / min and a span distance of 50 mm.

(6) DuPont impact strength: JIS K54
The impact strength at 23 ° C. was determined by measuring with an impact deformation method tester (method B) described in No. 00, calculating according to JIS K7211.

(7) Surface roughness: Surface roughness measuring device sur
fcom200C (manufactured by Tokyo Seimitsu Co., Ltd.) was used, and the tip of the stylus was 5 μmR made of diamond. The measurement site is 150 mm in the width direction and 50 in the flow direction from any point on the sheet.
mm sample is taken out and the measurement distance is 100 in the width direction.
mm was measured collectively.

Reference Example 1 Production of Linear Propylene Resin (PP1) Containing Component (a) According to the following procedure, 11 wt% of component (a) having [η] _A = 7.7 dl / g is contained. Linear propylene resin (PP
1) was produced.

[1] (Synthesis of solid catalyst component) After replacing a 200-liter SUS reaction vessel equipped with a stirrer with nitrogen, 80 liters of hexane, 6.55 mol of tetrabutoxytitanium, 2.8 mol of diisobutyl phthalate,
And 98.9 mol of tetraethoxysilane were added to make a uniform solution. Next, 51 liters of a solution of butylmagnesium chloride in diisobutyl ether having a concentration of 2.1 mol / liter was gradually added dropwise over 5 hours while maintaining the temperature in the reaction vessel at 5 ° C. After completion of dropping, the mixture was further stirred at room temperature for 1 hour and then washed with 70 liters of solid-liquid separator ruene at room temperature three times. Then, the slurry concentration is 0.6K
Toluene was added so as to be g / liter, then a mixed solution of 8.9 mol of n-butyl ether and 274 mol of titanium tetrachloride was added, and 20.8 mol of phthalic acid chloride was further added, followed by reaction at 110 ° C. for 3 hours. went. After completion of the reaction, 9
Washing with toluene was performed twice at 5 ° C. Then, after adjusting the slurry concentration to 0.6 kg / l, 3.13 mol of diisobutyl phthalate and 8.9 of n-butyl ether.
Mol and 137 mol of titanium tetrachloride were added, and the reaction was carried out at 105 ° C. for 1 hour. After completion of the reaction, solid-liquid separation was carried out at the same temperature, and then washing with 90 liters of toluene was carried out twice at 95 ° C. Then, after adjusting the slurry concentration to 0.6 Kg / liter, 8.9 mol of n-butyl ether and 137 mol of titanium tetrachloride were added, and the reaction was carried out at 95 ° C for 1 hour. After completion of the reaction, solid-liquid separation was performed at the same temperature, and washing with 90 liters of toluene was performed three times at the same temperature. Then, after adjusting the slurry concentration to 0.6 Kg / liter, 8.9 mol of n-butyl ether and 137 mol of titanium tetrachloride were added, and the reaction was carried out at 95 ° C for 1 hour. After completion of the reaction, solid-liquid separation was performed at the same temperature, 90 liters of toluene was washed at the same temperature 3 times, 90 liters of hexane was further washed 3 times, and dried under reduced pressure to obtain 11.0 kg of a solid catalyst component. Obtained. The solid catalyst component is titanium atom 1.9% by weight, magnesium atom 20% by weight, phthalic acid ester 8.6% by weight,
0.05% by weight of ethoxy groups, 0.21% by weight of butoxy groups
And had a good particle property without fine powder.

[2] (Preliminary activation of solid catalyst component) n-hexane (1.5 liters, triethylaluminum: 37.5 mmol, fully dehydrated and degassed in an autoclave made of SUS and having an internal volume of 3 liters), t-
3.75 mmol of butyl-n-propyldimethoxysilane and 15 g of the solid catalyst component obtained in the above [1] were added, and propylene was added while maintaining the temperature in the tank at 5 to 15 ° C.
g was continuously supplied over 30 minutes to perform pre-activation.

[3] (Polymerization of crystalline propylene polymer part (A)) In a polymerization tank made of SUS and having an internal volume of 300 liters, liquid propylene is maintained so that the polymerization temperature is 60 ° C. and the polymerization pressure is 27 kg / cm ² G. While supplying 57 kg / h,
Triethylaluminum 1.3 mmol / h, t-butyl-n-propyldimethoxysilane 0.13 mmol / h
h and 0.51 g / h of preactivated solid catalyst component
Was continuously supplied and propylene polymerization was carried out in the substantial absence of hydrogen to obtain a polymer of 2.0 kg / h. The amount of polymer produced at this time was 3920 g per 1 g of the catalyst,
As a result of sampling and analyzing a part thereof, the intrinsic viscosity was 7.7 dl / g. The obtained polymer was continuously transferred to the second tank as it was.

[4] (Polymerization of crystalline propylene polymer portion (B)) In a fluidized bed reactor with an internal volume of 1 m ³ equipped with a stirrer, the polymerization temperature was 80 ° C., the polymerization pressure was 18 kg / cm ² G, and the hydrogen in the gas phase part was used. While supplying propylene and hydrogen so as to maintain the concentration of 8 vol%, the catalyst-containing polymer transferred from the first tank and triethylaluminum 60 mmol / h,
By continuing the propylene polymerization continuously while supplying 6 mmol / h of t-butyl-n-propyldimethoxysilane, 18.2 kg / h of a polymer was obtained. The intrinsic viscosity of this polymer was 1.9 dl / g. From the above results, the amount of polymer produced during the polymerization of (B) was 31760 g per 1 g of the catalyst, the weight ratio of polymerization in the first tank and the second tank was 11:89, and the intrinsic viscosity of (B) was 1.2dl /
It was calculated as g.

[5] (Pelletization of the polymer) With respect to 100 parts by weight of this polymer powder, 0.1 part by weight of calcium stearate, trade name Irganox 1010
0.05 parts by weight (manufactured by Ciba Geigy) and 0.2 parts by weight of Sumilizer BHT (manufactured by Sumitomo Chemical Co., Ltd.) are added and mixed, and melt-kneaded at 230 ° C., and melt flow rate (MFR) is 12 g / 10. Min, molecular weight distribution (Mw / M
A pellet (PP1) having n) of 8.0 was obtained.

Example 1 (Extrusion Foaming Test) The component (a) having an intrinsic viscosity [η] a = 7.7 dl / g was added to 11 parts.
Linear propylene resin PP1 containing 1 wt% (MFR = 1
2 g / 10 minutes) and AW191 (Sumitomo Chemical Co., Ltd., a linear propylene resin containing 29% by weight of the component (b), the content of repeating units derived from ethylene is 37% by weight). Containing a crystalline ethylene-propylene copolymer (b), MFR = 11 g / 10 minutes) and HA100E (Sumitomo Chemical Co., Ltd., propylene alone) as a linear propylene-based resin for adjusting the shear viscosity. Copolymer, MFR = 310 g / 10 min), and E, which is an ethylene / 1-octene copolymer as component (c)
Using G8200 (Dupont Dow Elastomer Japan, density 0.87 g / cc, MFR = 4 g / 10 min),
PP1 / AW191 / HA100E / EG8200 = 2
The blended product at a weight ratio of 0 / 48.8 / 16.2 / 15 was granulated with a 65 mmφ single screw extruder to obtain a propylene resin composition for foam molding. Content of component (a) in the composition Wa = 11% by weight × 20/100 = 2.
2% by weight, content of component (b) = 29% by weight × 48.8
/100=14.2% by weight, content of component (c) = 15
% By weight. Left side of Expression 1 = 600 × EXP (−0.
6 × [η] a) = 5.9% by weight, right side = 100 ×
EXP (−0.6 × [η] a) = 1.0% by weight,
5.9 ≧ Wa (2.2) ≧ 1.0, which satisfies the formula 1. The shear viscosity of the entire composition at a temperature of 185 ° C and a shear rate of 2432 / s was 73 Pa · s, and the shear viscosity at a temperature of 185 ° C and a shear rate of 3648 / s was 61 Pa · s.

As a foaming agent and a foaming auxiliary agent, the weight ratio of baking soda / azodicarboxylic acid amide / zinc oxide is 90/5/5.
A 30% by weight masterbatch (polyethylene base) of the composite foaming agent was added to the above composition at 3.5 PHR and blended. The extruder has a gear pump at the tip of 120 m
mΦ single-screw extruder (L / D = 32, L is effective screw length, D is screw diameter) is used and 1500 mm
A device connected with a T-die of width (lip gap 0.4 mm, lip land 3 mm) was used. A raw material obtained by blending the composition with a foaming agent and a foaming aid is charged into an extruder hopper, melt-kneaded, cooled and adjusted to 180 ° C.,
The extrusion rate of 280 kg / hr was stably introduced into the T-die using a gear pump. The shear rate at the lip portion was found to be 2593 / s from Equation 5, which was a high production rate. A flat foam sheet extruded from a T-die was placed immediately after,
Further, it was cooled and molded by a large number of 300φ rolls whose cooling temperature was controlled to about 50 ° C., taken by a taker equipped with a nip roll, and then cut into a predetermined size by a cutter. The foamed sheet thus obtained had a foaming ratio of 3.0 times and a thickness of 3.0 mm. When the surface roughness was measured, it was smooth as shown in FIG. The flexural modulus is 3660 kg / cm ^{2 in} the MD direction and ^{2 in} the TD direction.
530 kg / cm ² , and the DuPont impact strength is 44.
It was a foamed sheet with a balance of bending and impact of ² kg · cm / cm ² .

[Comparative Example 1] Intrinsic viscosity [η] a = 7.7d
AW191A (Sumitomo Chemical Co., Ltd.) as a linear propylene-based resin PP1 (MFR = 12 g / 10 min) containing 11% by weight of the component (a) of 1 / g and a linear propylene-based resin containing 31% by weight of the component (b). Manufactured by Kogyo Co., Ltd., containing an amorphous ethylene-propylene copolymer (b) in which the content of repeating units derived from ethylene is 37% by weight, MF
R = 11 g / 10 minutes) and ethylene as the component (c).
FV401 which is a 1-hexene copolymer (manufactured by Sumitomo Chemical Co., Ltd., density 0.90 g / cc, MFR = 4 g / 10
Minutes), PP1 / AW191A / FV401 = 25
65mm blended at a weight ratio of / 65/10
The resin composition for foam molding was obtained by granulating with a φ single-screw extruder. Addition amount of component (a) in the composition Wa = 11% by weight
× 25/100 = 2.8% by weight, amount of component (b) added =
31% by weight × 65/100 = 20.2% by weight, and the amount of the component (c) added was 10% by weight. Left side of formula 1 = 6
00 × EXP (−0.6 × [η] a) = 5.9% by weight, right side = 100 × EXP (−0.6 × [η] a) =
1.0% by weight, 5.9 ≧ Wa (2.8) ≧ 1.0
Therefore, (Equation 1) was satisfied. However, the shear viscosity of the entire composition at a temperature of 185 ° C. and a shear rate of 2432 / s is 90 Pa · s, a temperature of 185 ° C., and a shear rate of 3
The shear viscosity at 648 / s was as high as 71 Pa · s.

The extrusion rate is 234 kg / h, which is lower than that in Example 1.
The same procedure as in Example 1 was carried out except that r (shear rate at the lip portion was 2167 / s). The foamed sheet thus obtained had a foaming ratio of 3.0 times and a thickness of 3.0 mm. When the surface roughness was measured, uneven swelling was observed as shown in FIG. The reason for lowering the extrusion amount from that in Example 1 is that this uneven swelling occurred remarkably and the evaluation was difficult. The bending elastic modulus was 4140 kg / cm ² in the MD direction, T
The D direction was 2510 kg / cm ² , and the DuPont impact strength was 30.8 kg · cm / cm ² .

[0059]

As described above, according to the present invention, a propylene-based resin composition for foam molding, which gives a foamed sheet excellent in productivity and smoothness, and foaming excellent in productivity and smoothness. A sheet and a method of manufacturing the sheet are provided. By using the propylene-based resin composition for foam molding of the present invention, a foamed sheet having good productivity, smoothness and bending impact properties can be obtained without impairing foamability. In particular, it is suitable for thin and high-magnification foam sheets with a narrow lip gap and high shear rate. The foam sheet is lightweight,
It is used for packaging, food containers, stationery, building materials, interior materials for automobiles, etc. by utilizing its heat insulating property.

[Brief description of drawings]

FIG. 1 is a result of measuring surface roughness of a foamed sheet obtained in Example 1.

2 is a surface roughness measurement result of the foamed sheet obtained in Comparative Example 1. FIG.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) (C08L 23/10 23:16) F term (reference) 4F074 AA17 AA24 AA25 AA98 AB05 BA03 BA13 BA95 CA22 DA02 DA23 DA32 DA33 DA34 DA35 DA50 DA59 4J002 BB052 BB053 BB111 BB121 BB152 BB153 DE206 EQ016 ER006 ET006 EV266 FD326 GC00 GG00 GL00 GN00 GT00

Claims (7)

[Claims] 1. A propylene resin composition for foam molding containing a crystalline propylene polymer (a) having an intrinsic viscosity of 7 dl / g or more, wherein the temperature is 185 ° C. and the shear rate is 2432.
Shear viscosity at 50 / s is 50 to 85 Pa · s,
A propylene-based resin composition for foam molding, which has a shear viscosity of 40 to 65 Pa · s at a temperature of 185 ° C. and a shear rate of 3648 / s. 2. The propylene resin composition for foam molding according to claim 1, which contains an amorphous ethylene / α-olefin copolymer (b) in addition to the above. 3. The propylene-based resin composition for foam molding according to claim 1 or 2, which contains a crystalline ethylene / α-olefin copolymer (c) in addition to the above. 4. The propylene resin composition for foam molding according to claim 3, wherein the crystalline ethylene / α-olefin copolymer (c) is an ethylene / 1-octene copolymer. 5. A method for producing a foamed sheet, which comprises mixing a foaming agent and a melted propylene-based resin composition for foam molding according to any one of claims 1 to 4, extruding the mixture through a die, and solidifying by cooling. 6. A foamed sheet obtained by the manufacturing method according to claim 5. 7. A propylene-based resin composition for foam molding according to claim 1, which has a foaming ratio of 1.5.
A foamed sheet having a thickness of 5 times and a thickness of 1 to 7 mm.