JP2004291623A - Multi-layered foamed sheet of propylene type resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide production of a multi-layered foamed sheet of a propylene type resin having a small degree of an undesirable scale like appearance. <P>SOLUTION: The multi-layered foamed sheet of a propylene type resin is produced by co-extrusion using a multi-manifold type multi-layered T die. The multi-layered foamed sheet of a propylene type resin comprises thermoplastic resin layers on the both surfaces of the foamed layer of a propylene type resin, and the multi-layered T die is one in which a distance L1 from the junction of resin flow pathways to the die outlet is 10-50 mm, a height t1 of the resin flow pathway at the position of immediately down from the junction of the resin flow pathways is 3-8 mm and a length of lipland L2 is 0-5 mm. The propylene type resin forming the foamed layer of a propylene type resin contains a propylene resin comprising a crystalline propylene polymer part (A) having a limiting viscosity of [η]=7-9 dl/g and its ratio in the total resin in the foamed layer of the propylene type resin falls within WA wt% in the [relation A] shown by 0.5WA≤a≤/(EXP([η]A<SP>c</SP>)+b) wherein a=250000, b=100 and c=1.15. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a method for producing a propylene-based resin multilayer foam sheet and a propylene-based resin multilayer foam sheet.

BACKGROUND ART Foam sheets made of propylene-based resin are used for packaging, mail boxes, partition boards, food containers, stationery, building materials, automobile interior materials, etc., utilizing their mechanical properties, light weight, heat resistance, oil resistance, and the like. When a propylene-based resin foam sheet is used for various purposes, it may be used as a multilayer foam sheet by laminating a film according to the purpose on the surface of the foam layer, or laminating a non-foam layer on the foam layer. Many.
As a method of manufacturing a multilayer foam sheet, the resin raw materials corresponding to each layer are plasticized and melted using a plurality of extruders, and the molten resin supplied from each extruder is laminated and integrated in a die and extruded out of the die. The coextrusion method is common. Patent Literature 1 discloses that coextrusion T-die foaming is performed in a coextrusion method by matching the fluidity of a polyolefin-based resin layer (A) and a foamable polyolefin-based resin layer (B) so that the thickness of each layer in the width direction is obtained. It is disclosed that distribution unevenness is improved.

JP-A-7-16971

Originally, the thickness distribution unevenness was such that the molten resin of each layer was merged into a layer in the die, and then the multilayer molten resin formed into a T-die outlet shape through a thinning and widening channel was transferred to the outside of the T-die. This is a defect that tends to occur in a T-die co-extrusion method using a feed block method of extruding and foaming. The present inventors have studied a method of manufacturing a multilayer foamed sheet by a co-extrusion method using a multi-manifold type multilayer T-die. In a general multi-manifold type multilayer T-die co-extrusion method, see Patent Document 1. It has been found that the problem of the appearance defect that a scale-like pattern with a diameter of about several centimeters appears rather than the large scale defect such as the uneven thickness distribution as described. The present invention provides a method for producing a propylene-based resin multilayer foam sheet with less scale-like appearance defects when producing a propylene-based resin multilayer foam sheet by co-extrusion using a multi-manifold type multilayer T die. Is what you do.

That is, the present invention relates to a method for producing a propylene-based resin multilayer foam sheet by co-extrusion using a multi-manifold type multilayer T die, wherein the propylene-based resin multilayer foam sheet has a thermoplastic resin on both sides of a propylene-based resin foam layer. The multilayer T-die has a resin layer, the distance L1 from the resin flow path junction to the die exit is 10 to 50 mm, the resin flow path height t1 immediately after the resin flow path junction is 3 to 8 mm, _A crystalline propylene polymer portion (A) which is a multilayer T-die having a length L2 of 0 to 5 mm and in which a propylene-based resin constituting a propylene-based resin foam layer has an intrinsic viscosity [η] _A = 7 to 9 dl / g. containing propylene resin having a ratio of the crystalline propylene polymer portion in the total resin constituting the propylene-based resin foam layer (a) is shown in W _a wt% of [formula a] It is a propylene-based resin multilayer foamed sheet manufacturing method of a circumference.
0.5 ≦ W _A ≦ a / (EXP ([η] _A ^C ) + b) [Formula A]
(However, a = 250,000, b = 100, c = 1.15)
The present invention is also a propylene-based resin multilayer foam sheet manufactured by the method for producing a propylene-based resin multilayer foam sheet.

ADVANTAGE OF THE INVENTION The manufacturing method of the multilayer foam sheet made of a propylene-based resin of this invention can manufacture the multilayer foamed sheet made of a propylene-based resin which has few scaly appearance defects and a beautiful appearance. Further, the propylene-based resin multilayer foam sheet of the present invention is a propylene-based resin multilayer foam sheet having a small scale-like appearance defect and a beautiful appearance.

The present invention is a method for producing a propylene-based resin multilayer foam sheet by co-extrusion using a multi-manifold type multilayer T die. In the multilayer T die according to the present invention, the distance L1 from the resin flow path junction to the die outlet is 10 to 50 mm, the resin flow path height t1 immediately after the resin flow path junction is 3 to 8 mm, and the lip land length L2 is This is a multi-manifold type multilayer T die of 0 to 5 mm.

The multi-manifold type multilayer T-die is a T-die of a type in which a resin constituting each layer is introduced into the T-die, the width of the resin is increased, the layers are merged, and extruded from a die outlet. In the multilayer T-die according to the present invention, the distance L1 from the resin flow path junction to the die outlet is 10 to 50 mm, preferably 10 to 40 mm. If the distance L1 from the resin flow path junction to the die exit is too long, scale-like appearance defects tend to occur.

Normally, the height t1 of the resin flow path immediately after the junction of the resin flow paths is much larger than the lip gap t2 at the exit of the die. Therefore, if the distance L1 is too short, the resin is rapidly compressed from the junction of the resin flow path to the die outlet, and there is a concern that poor appearance of the foamed sheet due to stagnation or deterioration of the resin may occur.

The resin flow path height t1 immediately after the resin merging portion in the multilayer T die is a height in a direction perpendicular to the extrusion direction and the foam sheet width direction when the resin is extruded from the multilayer T die to form a foam sheet. That's it. The resin flow path height t1 immediately after the resin merging portion is 3 to 8 mm, and preferably 5 to 7 mm. If the height t1 is too low, scale-like appearance defects are liable to occur, and if the height t1 is too high, the pressure in the lip portion is reduced and bubbles grow in the die, so that the appearance such as foam breakage or outgassing occurs. There is a tendency for defects to occur.

In the present invention, the length L2 of the lip land in the multilayer T die is 0 to 5 mm, preferably 0 to 3 mm. If the length L2 of the lip land is too long, scale-like appearance defects are likely to occur.

The lip gap t2 in the multilayer T-die may be appropriately set according to the overall thickness of the multilayer foam sheet to be obtained, and is usually about 0.1 to 2 mm. For example, when manufacturing a multilayer foam sheet having an expansion ratio of about 4 and a thickness of about 4 mm, the lip gap t2 is preferably set to 0.6 to 0.9 mm.

The joining angle θ between the adjacent resin flow paths is preferably 40 to 80 °, and more preferably 50 to 70 °. If the confluence angle θ is too large, poor appearance tends to occur. On the other hand, if the merging angle θ is too small, the rigidity of the resin flow path at the merging portion becomes insufficient, so that the resin pressure before the merging becomes uneven due to the resin pressure, and the thickness distribution in the width direction of each layer of the multilayer foamed sheet is reduced. Tends to be larger.

The propylene-based resin multilayer foam sheet of the present invention has a propylene-based resin foam layer. The propylene-based resin constituting the propylene-based resin foam layer contains a propylene resin having a crystalline propylene polymer portion (A) having an intrinsic viscosity [η] _A = 7 to 9 dl / g, and constitutes the propylene-based resin foam layer. The ratio of the crystalline propylene polymer portion (A) in the total resin to be formed is in the range indicated by W _A wt% in [Formula A].
0.5 ≦ W _A ≦ a / (EXP ([η] _A ^C ) + b) [Formula A]
(However, a = 250,000, b = 100, c = 1.15)

The intrinsic viscosity [η] _A of the crystalline propylene polymer portion (A) is 7 to 9 dl / g, preferably 7.2 to 8.6 dl / g, and more preferably 7.4 to 8.2 dl. / G. The intrinsic viscosity [η] _A can be measured in tetralin at 135 ° C. using an Ubbelohde viscometer. If the intrinsic viscosity [η] _{A of the} crystalline propylene polymer portion (A) is too high or too low, a scale-like appearance defect is likely to occur.

The propylene-based resin foamed layer is a resin in which the proportion of the crystalline propylene polymer portion (A) in the entire resin constituting the propylene-based resin foamed layer is in the range indicated by W _A wt% in the following [Formula A]. Be composed.
0.5 ≦ W _A ≦ a / (EXP ([η] _A ^C ) + b) [Formula A]
(However, a = 250,000, b = 100, c = 1.15)
By using a resin in which the proportion of the crystalline propylene polymer portion (A) is in the above range for the foamed layer, it is possible to produce a scale-shaped propylene-based resin-made multilayer foamed sheet having few appearance defects. If the proportion of the crystalline propylene polymer portion (A) in the total resin for the foam layer is too small, it tends to be difficult to produce a foam sheet having a high expansion ratio.

As the propylene resin having a crystalline propylene polymer portion (A) having an intrinsic viscosity [η] _A = 7 to 9 dl / g, the following propylene polymer (T) is preferably used. That is, polymerization including a step of producing a crystalline propylene polymer portion (A) having an intrinsic viscosity of 7 to 9 dl / g or more and a step of producing a crystalline propylene polymer portion (B) having an intrinsic viscosity of less than 3 dl / g. It is a propylene polymer (T) obtained by the method, having an intrinsic viscosity of less than 3 dl / g and a proportion of the crystalline propylene polymer portion (A) of 0.5% by weight or more and less than 35% by weight.

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

(A) and (B) are each a crystalline propylene polymer portion having a polypropylene crystal structure, and a homopolymer of propylene or propylene and an amount of ethylene and / or α-olefin that does not lose crystallinity. Copolymers with comonomers such as 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 differs depending on the type of comonomer. For example, in the case of ethylene, the amount of ethylene-derived structural units in the copolymer is usually 10% by weight or less, and other α- In the case of an olefin, the amount of the α-olefin-derived constituent unit in the copolymer is usually 30% by weight or less. (A) and (B) may have the same composition or different compositions. (A) and (B) may be combined in a block manner. Further, (A) and (B) may be combined in a block manner, and other (A) and (B) may coexist.

In addition to the above, the crystalline propylene polymer portion (B) may be a polymer portion in which an amorphous ethylene / α-olefin copolymer is dispersed in a crystalline propylene polymer.

The propylene polymer (T) can be produced using, for example, a solid catalyst containing a Ti atom, a Mg atom, and a halogen atom, and specifically, a method described in JP-A-11-228629 is exemplified. Can be

The resin for the foamed layer may be blended with another olefin-based resin such as an ethylene-based resin such as low-density polyethylene or high-density polyethylene so as not to impair the effects of the present invention. The ratio of the crystalline propylene polymer portion (A) in the present invention is a ratio in all the resins constituting the foamed layer.

From the viewpoint of fluidity and processability, the MFR of all the resins constituting the foamed layer is preferably 5 g / 10 min or more and 30 g / 10 min or less. If the MFR is too high, the melt tension required for foaming cannot be maintained, and if the MFR is too low, the effect on processability, specifically, the heat generated by shearing and the rise in resin temperature are large. It is more preferably from 8 g / 10 min to 25 g / 10 min, and even more preferably from 10 g / 10 min to 20 g / 10 min. When the foamed layer is composed of a plurality of resins, the MFR of the resin is the MFR of a mixture of the resins constituting the foamed layer.

The foaming agent used for forming the foamed layer in the present invention is not particularly limited, and known physical foaming agents and chemical foaming agents can be used alone or in combination. As the physical foaming agent, carbon dioxide gas, nitrogen gas, air, propane, butane, pentane, hexane, dichloroethane, dichlorodifluoromethane, dichloromonofluoromethane, trichloromonofluoromethane, and the like can be used.Nitrogen gas, carbon dioxide gas, It is preferable to use a safe and environmentally friendly inorganic gas such as air. From the viewpoint of safety and solubility in the propylene-based resin, it is more preferable to use carbon dioxide gas. When carbon dioxide gas is used, it is preferable to inject into the propylene-based resin in a supercritical state of 7.4 MPa or more and 31 ° C. or more from the viewpoint of diffusion into the resin and solubility.

Chemical blowing agents include organic acids such as citric acid, sodium citrate, and stearic acid, isocyanate compounds such as baking soda, azodicarbonamide, tolylene diisocyanate, and 4,4'-diphenylmethane diisocyanate, azobisbutyronitrile, and barium azo. Azo such as dicarboxylate, diazoaminobenzene and trihydrazinotriazine, diazo compounds, hydrazine derivatives such as benzene sulfonyl hydrazide, P, P'-oxybis (benzenesulfonyl hydrazide), toluene sulfonyl hydrazide, N, Nitroso compounds such as N'-dinitroso pentamethylene tetramine, N, N'-dimethyl-N, N'-dinitroso terephthalamide, P-toluenesulfonyl semicarbazide, 4,4'oxybisbe Semicarbazide compounds such as Zen semicarbazide, azide compounds, etc. can be used triazole compound. In particular, it is preferable to use any of baking soda, citric acid, and azodicarbonamide.

When a chemical foaming agent is used, a foaming aid may be used in combination to adjust the decomposition temperature and decomposition rate. For example, since azodicarbonamide alone has a high decomposition temperature of about 200 ° C., when processing at a low temperature, a small amount of zinc oxide, zinc stearate, urea, or the like can be used as a foaming aid.

When using a physical foaming agent, a cell nucleating agent may be used in combination. Foam nucleating agents include talc, silica, diatomaceous earth, calcium carbonate, magnesium carbonate, barium sulfate, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, calcium silicate, zeolite, mica, clay, wollastonite, hydrotalcite Polymer beads such as magnesium oxide, zinc oxide, zinc stearate, calcium stearate, PMMA, synthetic aluminosilicate and the above-mentioned chemical foaming agents can be used.

The multilayer foamed sheet made of propylene-based resin in the present invention has a thermoplastic resin layer on both sides of the foamed propylene-based resin layer. The thermoplastic resin layer laminated on one side of the propylene-based resin foam layer may be one layer or two or more layers. The thermoplastic resin layers located on both sides of the foamed layer may have the same composition or may be composed of different resins.

As the thermoplastic resin constituting the thermoplastic resin layer, known resins can be used, and examples thereof include an ethylene-based resin such as low-density polyethylene and high-density polyethylene, and an olefin-based resin such as propylene-based resin. The resin constituting the foam layer may be the same resin. One kind of resin constituting the thermoplastic resin layer may be used, or two or more kinds of resins may be used in combination. Preferably, 50% by weight or more of the resin constituting the thermoplastic resin layer is a propylene-based resin.

The propylene-based resin multilayer foam sheet of the present invention may have a layer other than the foam layer and the thermoplastic resin layer. The resin constituting both outermost layers of the multilayer foamed sheet made of a propylene-based resin is preferably a propylene-based resin having an MFR of 0.1 to 10 g / 10 min from the viewpoint of rigidity and impact resistance. When the propylene-based resin multilayer foam sheet of the present invention has three layers, the outermost layer is the thermoplastic resin layer.

Various low molecular weight or high molecular weight additives may be blended into each layer constituting the propylene-based resin multilayer foam sheet, if necessary. For example, an antistatic agent, a flame retardant, a filler, an antioxidant, a copper damage inhibitor, a weathering agent, an ultraviolet absorber, a lubricant, a pigment, a foaming agent, an adhesion improver, and the like are used. In particular, by adding an additive according to the application to the outermost layer, a function according to the application can be imparted.

The method for producing a propylene-based resin-made multilayer foam sheet of the present invention uses a multi-manifold-type multilayer T-die as described above, except that the above-mentioned resin is used as a resin constituting the propylene-based resin-made multilayer foam sheet. Can employ a known method for producing a multilayer foam sheet. For example, in a multi-manifold type multilayer T-die in which a resin constituting each layer and a foaming agent are melt-kneaded in an extruder, and the molten resin composition in the extruder is connected to the extruder through a resin flow path. Send to The molten resin composition constituting each layer widened in the multilayer T-die joins in a layered manner at a resin flow passage merging portion, and is co-extruded from the die outlet into the atmosphere. The extruded plate-shaped molten sheet is brought into contact with a number of cooling-temperature-controlled rolls placed immediately after the die, or is passed while making contact between two cooling-temperature-controlled plate-like flat plates. This is a method for producing a propylene-based resin multilayer foam sheet by cooling and forming by a known cooling and forming method, and then taking up with a take-off machine provided with a nip roll and cutting to a predetermined size with a cutting machine.

As the extruder, a single-screw or multi-screw extruder can be used, and a tandem extruder combining a plurality of extruders can also be used. As the extruder used for kneading the resin and the foaming agent constituting the foamed layer, a twin-screw extruder is preferable. The extruder has a large amount of extrusion per one rotation of the screw and can obtain a predetermined amount of extrusion at a low rotation. It is more preferable to use an extruder having a structure that generates less heat generated by shearing. A cooling medium may be circulated through the screw body to control the temperature.

A gear pump may be provided between the extruder and the multilayer T-die, and a fixed-quantity feeder may be provided for supplying raw materials. In order to control the gear pump inlet pressure to be constant, a control system that feeds back the gear pump inlet pressure value to the rotation speed of the screw or gear pump and the raw material supply amount is also effective for stabilizing the extruded foaming state.
Inserting a static mixer or the like into the adapter connecting the extruder and the multilayer T-die to make the resin temperature uniform is also effective in making the foaming state inside the foam sheet uniform.
When a physical foaming agent is used, the foam layer extruder has a structure in which the physical foaming agent can be pressed in during resin kneading. The physical blowing agent is press-fitted after the resin is sufficiently melt-plasticized. After the injection of the physical foaming agent, the resin and the foaming agent are sufficiently mixed and homogenized, and the resin temperature is controlled to be suitable for foaming.

The multilayer T-die co-extrusion method in the present invention is a method using a multi-manifold type multilayer T-die. However, when the number of the propylene-based resin multilayer foam sheets to be produced is, for example, five or more, the weight and cost of the die are reduced. To increase the volume, the layered molten sheet previously laminated with the feed block may be further laminated with another layer in the multi-manifold type multilayer T die used in the present invention to form a multilayer.

The expansion ratio and thickness of the propylene-based resin multilayer foam sheet of the present invention are not particularly limited, but usually, the expansion ratio of the entire sheet is 1.3 to 7 times, and the thickness of the entire sheet is 1 to 7 mm. .
The ratio of the thickness of each outermost layer to the total thickness of the sheet is preferably 0.05 to 1%. In such a case, for example, when the thickness of the entire sheet is 4 mm, the outermost layers are very thin, 2 to 40 μm each. The outermost layer often adds an antistatic agent, a pigment, or the like in order to provide a function according to the application. By making the outermost layer thinner, the amount of additives can be reduced to a small amount, so that a low-cost, high-performance multilayer foamed sheet made of a propylene-based resin can be obtained.
A propylene-based resin multilayer foam sheet having a thin outermost layer and a small scale-like appearance defect can be obtained for the first time by producing it by the production method of the present invention.

The multilayer foamed sheet of the present invention may be optionally subjected to surface treatment such as corona treatment, ozone treatment, or application of an antistatic agent, which is usually performed on the surface of the propylene-based resin foamed sheet.

A skin material such as a sheet or a film may be laminated and bonded to one or both surfaces of the multilayer foam sheet obtained in the present invention, depending on the application. As the skin material such as a sheet or film for lamination, a known material can be used depending on the use. For example, a metal sheet such as aluminum or iron, a thermoplastic resin, paper, a thin sheet made of synthetic paper, or the like can be used. No. A nonwoven fabric or woven fabric made of a thermoplastic material, a plant material such as hemp, or an inorganic material such as glass may be laminated. Further, decoration such as embossing or printing may be applied to the surface of the thin plate used. The foam may be laminated and bonded as a skin material.

For example, when a propylene-based multilayer foam sheet is used for food packaging, it is preferable to laminate a propylene-based resin film or a gas barrier resin film having a thickness of 10 to 100 μm. As the gas barrier resin, an ethylene / vinyl alcohol copolymer, polyvinylidene chloride, polyvinyl alcohol, polyamide, or the like can be used. In addition, these gas barrier resins may be used alone or as a mixture, or two or more kinds of films made of the gas barrier resin may be laminated and used.

When the propylene-based resin multilayer foam sheet is used for an automobile interior material, it is preferable to laminate a nonwoven fabric, a woven fabric, a carpet, or the like. In addition, when used for packaging purposes, for example, as a partition plate for a box, a buffer sheet may be laminated to protect the contents.

The method of laminating the skin material to the propylene-based resin multilayer foam sheet is not particularly limited. For example, a method in which an adhesive is applied to the foam sheet surface and laminated, a skin material in which an adhesive resin film is laminated is used. Use, a method of heating and melting the film surface of the adhesive resin and laminating the foamed sheet, a method of melting and laminating the laminated surface of the skin material and the foamed sheet using a heater or hot air, etc., the molten resin and the skin material A method of extruding and laminating with a foamed sheet and laminating may be mentioned.

The propylene-based resin multilayer foam sheet or skin material laminated multilayer foam sheet of the present invention can be subjected to thermoforming such as vacuum forming. As the thermoforming, thermoforming can be performed by a known method such as vacuum forming or hot crease processing. Since the multilayer foam sheet of the present invention has a small thickness distribution and fine cells, it is excellent in thermoformability.

The multilayer foamed sheet made of propylene-based resin of the present invention can be used for packaging, box passing, partition boards, food containers, stationery, building materials, automobile interior materials and the like.

  Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. The evaluation methods used in Examples and Comparative Examples are described below.

(1) Intrinsic Viscosity of Polymer The polymer was measured at 135 ° C. in tetralin using an Ubbelohde viscometer. Note that the intrinsic viscosity of the crystalline propylene polymer portion (B) is determined to be additive from the intrinsic viscosity of the crystalline propylene polymer portion (A) and the entire propylene polymer (T), and is disclosed in JP-A-11-228629. It was determined from the described formula.

(2) MFR
According to JIS K7210, measurement was performed at a temperature of 230 ° C. and a load of 2.16 kgf. The unit is g / 10 minutes.

(3) In accordance with JIS K7112, the density ρf of the entire multilayer foam sheet is determined by an underwater substitution method, and the ratio to the density ρ0 (0.9 g / cm ³ ) of the resin constituting the multilayer foam sheet, that is, ρ0 / ρf Thus, the expansion ratio of the entire multilayer foam sheet was calculated.

(4) Surface resistivity In the width direction of the multilayer foamed sheet, sampling was performed at five locations with a size of 100 mm x 100 mm, and the surface resistivity of each sample was measured using a surface resistance measuring instrument (SME-8310 manufactured by Toa Denpa Kogyo Co., Ltd.). Measured at 50% relative humidity and 23 ° C. room temperature. The logarithmic average value at five locations in the width direction of the sample front and back was determined as a representative value.

[Reference Example 1] (Production of propylene-based resin PP1)
[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 charged, and a homogeneous solution was added. did. Next, 51 l of a solution of butylmagnesium chloride in diisobutyl ether having a concentration of 2.1 mol / l was gradually added dropwise over 5 hours while maintaining the temperature in the reaction vessel at 5 ° C. After completion of the dropwise addition, the mixture was further stirred at room temperature for 1 hour, and then washed with 70 liters of solid-liquid separator Ruen at room temperature three times.
Next, toluene was added so that the slurry concentration became 0.6 kg / 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. The reaction was performed at 110 ° C. for 3 hours. After completion of the reaction, washing with toluene was performed twice at 95 ° C.
Next, after adjusting the slurry concentration to 0.6 kg / liter, 3.13 mol of diisobutyl phthalate, 8.9 mol of n-butyl ether and 137 mol of titanium tetrachloride were added, and the mixture was reacted at 105 ° C. for 1 hour. After the completion of the reaction, the mixture was subjected to solid-liquid separation at the same temperature, followed by washing twice at 95 ° C. with 90 l of toluene.
Next, 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 mixture was reacted 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.
Next, 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 mixture was reacted at 95 ° C. for 1 hour. After completion of the reaction, solid-liquid separation was carried out at the same temperature, washing was carried out three times with 90 liters of toluene at the same temperature, washing was further carried out three times with 90 liters of hexane, followed by drying under reduced pressure to obtain 11.0 kg of solid catalyst component. Obtained.
The solid catalyst component contains 1.9% by weight of titanium atom, 20% by weight of magnesium atom, 8.6% by weight of phthalic acid ester, 0.05% by weight of ethoxy group, and 0.21% by weight of butoxy group. Particle properties.

[2] (Pre-activation of solid catalyst component)
1.5 L of n-hexane, 37.5 mmol of triethylaluminum, 3.75 mmol of t-butyl-n-propyldimethoxysilane, which was sufficiently dehydrated and degassed in a SUS autoclave having an internal volume of 3 liters and equipped with a stirrer, 15 g of the solid catalyst component obtained in [1] was added, and 15 g of propylene was continuously supplied over 30 minutes while preserving the temperature in the vessel at 5 to 15 ° C. to perform preactivation.

[3] (Polymerization of crystalline propylene polymer portion (A))
In a SUS polymerization tank having an internal volume of 300 liters, while supplying liquid propylene at 57 kg / h so as to maintain a polymerization temperature of 60 ° C. and a polymerization pressure of 27 kg / cm ² G, 1.3 mmol / h of triethylaluminum, t 1.13 mmol / h of -butyl-n-propyldimethoxysilane and 0.51 g / h of the preactivated solid catalyst component are continuously fed to carry out propylene polymerization in the substantial absence of hydrogen. 0 kg / h of polymer was obtained. At this time, the produced amount of the polymer was 3920 g per 1 g of the catalyst, and as a result of sampling and analyzing a part thereof, the intrinsic viscosity [η] _A was 7.7 dl / g. The obtained polymer was continuously transferred to the second tank as it was.

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

[5] (Pelletization of polymer (T))
With respect to 100 parts by weight of the polymer (T) powder obtained in [4], 0.1 parts by weight of calcium stearate, 0.05 parts by weight of Irganox 1010 (manufactured by Ciba Geigy), and Sumilizer BHT (Sumitomo) 0.2 parts by weight (manufactured by Chemical Industry Co., Ltd.) were added, mixed and melt-kneaded at 230 ° C. to obtain pellets (propylene-based resin PP1) having an MFR of 12 g / 10 min.

[Example 1] (Extrusion foaming test)
A multilayer foamed sheet made of a propylene-based resin having two and three layers of a thermoplastic resin layer / a foamed layer / a thermoplastic resin layer was prepared by the method described below. In the first embodiment, the thermoplastic resin layer corresponds to the outermost layer.
A 104 mmφ co-rotating twin screw extruder (L / D = 32, L is an effective screw length, D is a screw diameter) equipped with a gear pump at the tip as a foam layer extruder, and a 75 mmφ as a thermoplastic resin layer extruder A single-screw extruder (L / D = 32) was used, and a multi-manifold type multilayer T die illustrated in FIGS. 1 and 2 having a die outlet flow width of 1600 mm was used. The resin flow path merging angle θ in the multilayer T die is 60 °, the distance L1 from the resin flow path merging section to the die outlet is 36 mm, the length of the lip land L2 is 3 mm, and the flow path gap t1 immediately after the merging section is 6 mm, and the lip gap t2 was 0.6 mm.

50 parts by weight of the propylene-based resin PP1 (MFR = 12 g / 10 min) obtained in Reference Example 1 [5] above, and propylene-based resin PP2 (Noblen AW191A manufactured by Sumitomo Chemical Co., Ltd. (MFR = 11 g / 10 min) )) And 10 parts by weight of linear low-density polyethylene PE1 (Sumitomo Chemical Co., Ltd., Sumikasen E, FV401 (MFR = 4 g / 10 minutes)) were mixed, and a foam nucleating agent was used. (Nippon Boehringer Ingelheim Co., Ltd., Hydrocelol CF40E) 0.5PHR blended resin for foaming layer is fed into a foaming layer extruder hopper via a quantitative feeder and melt-kneaded in the extruder. At a position where melting has advanced (L / D = 20), 0.5 PHR of liquefied carbon dioxide gas was injected at a high pressure using a diaphragm type metering pump. After sufficiently melting and kneading the molten resin and carbon dioxide, the mixture was cooled and adjusted to 180 ° C., and was stably introduced into the multi-manifold type multilayer T-die at a discharge rate of 160 kg / h using a gear pump.
Incidentally, the content W _A intrinsic viscosity [eta] _A is 7.7 dl / g, also crystalline propylene polymer portion of the total resin foam layer of the crystalline propylene polymer portion (A) (A) 5 .50 wt%, the right side of [Equation A] was 7.16, which satisfied [Equation A]. Further, the MFR of the resin for a foam layer composed of PP1, PP2 and PE1 was 11 g / 10 minutes.
Next, 80 parts by weight of a propylene-based resin PP3 (manufactured by Sumitomo Chemical Co., Ltd., Noblen AS171G (MFR = 1 g / 10 min)) as a resin for the thermoplastic resin layer, and an antistatic agent (manufactured by Sanyo Chemical Industries, Ltd.) , Perestat 300) in a mixture of 20 parts by weight. The mixture is put into an extruder hopper for the outermost layer through a fixed-quantity feeder, melt-kneaded in the extruder, cooled and adjusted to 200 ° C., and introduced into a multi-manifold multilayer T-die at a discharge rate of 5 kg / h. did. The molten resin constituting the foamed layer and the molten resin constituting the thermoplastic resin layer were joined at the resin flow passage merging portion and laminated in layers, and then extruded from the die outlet as a flat molten sheet. The plate-shaped molten sheet is formed by cooling with a large number of 210φ rolls, which are cooled to about 60 ° C. and placed immediately after the die, taken up by a take-up machine equipped with a nip roll, and then cut to a predetermined size by a cutting machine. did.
The resulting multilayer foamed sheet had a total expansion ratio of 4.0 times and a thickness of 4.0 mm, the thickness of each thermoplastic resin layer was 17 μm, and the ratio of one thermoplastic resin layer to the total thickness of the sheet was 0.43. %Met. No scaly appearance defect was observed in the multilayer foam sheet, and the surface resistivity was 10 11 Ω / □.

[Reference Example 2] (Production of propylene-based resin PP4)
In the same manner as in Reference Example 1, the following linear propylene-based resin PP4 was produced.
(A) intrinsic viscosity 8.5 dl / g (9.5 wt%), (B) intrinsic viscosity 1.2 dl / g (90.5 wt%), (T) intrinsic viscosity 1.9 dl / g, (T) ) Has an MFR of 11 g / 10 min.

[Comparative Example 1]
The procedure was performed in the same manner as in Example 1 except that the propylene-based resin PP4 was used instead of the propylene-based resin PP1.
The intrinsic viscosity [η] _A of the crystalline propylene polymer portion (A) was 8.5 dl / g. The content W _A crystalline propylene polymer portion of the total resin foam layer (A) and the most 4.75 wt%, because the right side of Expression A] is 2.04, and satisfies the formula A] I didn't. Further, the MFR of the whole resin for the foam layer composed of PP4, PP2 and PE1 was 10 g / 10 minutes.
As a result, a scale-like appearance defect was conspicuous, and it was impossible to evaluate the thermoplastic resin layer thickness and the surface resistivity.

[Example 2]
The lip gap t2 was set to 1.0 mm. In addition, a blend of 12.5 parts by weight of the propylene-based resin PP4, 77.5 parts by weight of the propylene-based resin PP2, and 10 parts by weight of the linear low-density polyethylene PE1 was used as the resin for the foamed layer. The added amount of the liquefied carbon dioxide gas was 0.38 PHR, and the discharge amount of the foamed layer was 300 kg / h.
Incidentally, the intrinsic viscosity [eta] _A is 8.5dl / g of the crystalline propylene polymer portion in the resin foam layer (A), In addition, the content W _A is 1.19Wt%, the right side of Expression A] Since it was 2.04, [Equation A] was satisfied. The MFR of all resins for the foamed layer was 10 g / 10 minutes.
Except as described above, the same procedure as in Example 1 was carried out. As a result, the obtained multilayer foamed sheet had a foaming ratio of 3.0 times and a thickness of 4.0 mm as a whole, the thermoplastic resin layers each having a thickness of 11 μm, and one thermoplastic resin layer. The ratio of the resin layer to the entire sheet thickness was 0.28%. The thickness of each thermoplastic resin layer was 17 μm, and the ratio of one thermoplastic resin layer to the entire thickness of the sheet was 0.43%. No scale-like appearance defect was observed, and the surface resistivity was as good as 10 11 Ω / □.

[Comparative Example 2]
The same procedure as in Example 2 was performed except that a blend of 25 parts by weight of the propylene-based resin PP4, 65 parts by weight of the propylene-based resin PP2, and 10 parts by weight of the linear low-density polyethylene PE1 was used as the resin for the foamed layer. .
The content W _A intrinsic viscosity [eta] _A is 8.5dl / g, the crystalline propylene polymer portion of the total resin foam layer of the crystalline propylene polymer portion (A) (A) is 2.38wt %, And the right side of [Equation A] was 2.04, so that [Equation A] was not satisfied. The MFR of the foam layer resin composed of PP4, PP2 and PE1 was 10 g / 10 minutes.
As a result, a scale-like appearance defect was conspicuous, and it was impossible to evaluate the thermoplastic resin layer thickness and the surface resistivity.

[Comparative Example 3]
Example 1 was repeated except that the distance L1 from the junction to the die exit was set to 48 mm, and the length L2 of the lip land was set to 15 mm. Rate evaluation was not possible.

It is a drawing showing an example of a channel section of a multilayer T die by a multi-manifold method in the present invention. FIG. 2 is a drawing showing one example of a resin flow channel cross section in which a resin flow channel merging portion in FIG. 1 is enlarged.

Explanation of reference numerals

1: Multi-manifold type multilayer T-die 2: Lip (top)
3: Lip (bottom)
4: Manifold for foam layer 5: Choke bar for foam layer 6: Manifold for thermoplastic resin layer (top)
7: Choke bar for thermoplastic resin layer (top)
8: Manifold for thermoplastic resin layer (bottom)
9: Choke bar for thermoplastic resin layer (bottom)
10: Resin flow path junction 11: Resin flow path 12: Resin flow path 13: Resin flow path L1: Distance L2 from resin flow path junction to die exit L2: Length of lip land t1: Resin flow path height t2 : Lip gap θ: Resin channel merging angle

Claims (3)

A method for producing a propylene-based resin multilayer foam sheet by co-extrusion using a multi-manifold multilayer T-die, wherein the propylene-based resin multilayer foam sheet has thermoplastic resin layers on both sides of a propylene-based resin foam layer. The multilayer T die has a distance L1 from the resin flow path junction to the die exit of 10 to 50 mm, a resin flow path height t1 immediately after the resin flow path junction of 3 to 8 mm, and a lip land length L2 of 0. A propylene resin having a crystalline propylene polymer portion (A) having a limiting viscosity [η] _{A of} 7 to 9 dl / g. contained, the proportion of the crystalline propylene polymer portion in the total resin constituting the propylene-based resin foam layer (a) is in the range shown in W _a wt% of [formula a] propylene Method for producing a system resin multilayer foamed sheet.
0.5 ≦ W _A ≦ a / (EXP ([η] _A ^C ) + b) [Formula A]
(However, a = 250,000, b = 100, c = 1.15) The method for producing a propylene-based resin multilayer foam sheet according to claim 1, wherein the resin constituting both outermost layers of the propylene-based resin multilayer foam sheet is a propylene resin having an MFR of 0.1 to 10 g / 10 minutes. A method for producing a propylene-based resin multilayer foam sheet, wherein the ratio of each outermost layer to the total thickness of the propylene-based resin multilayer foam sheet is 0.05 to 1%. A multilayer foamed sheet made of a propylene-based resin produced by the method according to claim 1.

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