WO2007004524A1

WO2007004524A1 - Constructional heat-insulating foam board and process for production thereof

Info

Publication number: WO2007004524A1
Application number: PCT/JP2006/313028
Authority: WO
Inventors: Katsuaki Oono; Toru Itaya; Minoru Sugawara; Yasuhiko Otsuki; Chunxiao Zhang; Kazuhiro Baba
Original assignee: Asahi Fiber Glass Company, Limited
Priority date: 2005-06-30
Filing date: 2006-06-29
Publication date: 2007-01-11
Also published as: KR20080042046A; JPWO2007004524A1; CN101203552A

Abstract

The invention provides a constructional heat-insulating foam board of a polyolefin resin composition which exhibits excellent extrusion foamability and excellent heat insulation performance and which is recyclable and can be produced at a low cost continuously and stably. A constructional heat-insulating foam board, characterized by being produced by expanding a polyolefin resin composition containing a linear polypropylene resin exhibiting a melt tension of 5 to 30g at 230ºC with a blowing agent containing supercritical carbon dioxide as the essential component at an expansion ratio of 10 or above.

Description

Specification

Foam board for heat insulating building material and method for manufacturing the same

Technical field

TECHNICAL FIELD [0001] The present invention relates to a foam board for a heat insulating building material of a polyolefin resin composition and a method for producing the same.

Background art

[0002] Foams of polyolefin resin compositions are characterized by their excellent balance between performance and cost, and the recyclability of resins that have been sought in recent years. Widely used in packaging cushioning applications.

[0003] For example, as a heat insulating building material application, a polypropylene resin or a foam board of polyethylene resin is applied to the inside of a floor or wall of a building, exhibits excellent heat insulating performance, and is widely accepted in the market.

[0004] These foams of a polyolefin resin composition are widely used in the world as such very useful materials, and many production methods have been studied and implemented. Currently, there are roughly two methods for producing foams of polyolefin resin compositions.

[0005] The first production method is a so-called bead method, in which a foaming agent such as hydrocarbon is added to a polyolefin resin composition pellet dispersed in water or the like in a pressurized sealed container. After impregnation under high temperature and high pressure, it is rapidly released to atmospheric pressure, so-called pre-expanded particles are produced, the pre-expanded particles are filled in a mold, and heated and cooled to obtain a molded product in the mold. is there.

[0006] Foam boards made of polyolefin resin composition can be produced by this bead method, but the foam produced by the usual bead method has an average cell diameter of about 200 to 500 xm. Insufficient thermal performance cannot be obtained for use as a heat insulating building material. In addition, the bead method is a batch production method, and it is necessary to perform in-steam molding after the pellet production process and pre-expanded particle production process. There is a drawback that the manufacturing cost is higher than possible.

[0007] The second production method is a so-called extrusion method, and the polyolefin is used as an extruder. Resin composition particles are added, and if necessary, using a hydrocarbon or chemical foaming agent as a foaming agent, melt and knead under heating and pressurization, and then obtain a foam through a die designed in a predetermined shape Is the method.

[0008] Regarding this extrusion method, for example, in Patent Document 1, a polyfunctional monomer and a thermal decomposable foaming agent are added to a polypropylene resin, melt-mixed in advance, and irradiated with an electron beam to crosslink the polypropylene resin. And a method of further decomposing and foaming the pyrolyzable foaming agent by heating it further.

[0009] Further, in the extrusion method described in Patent Document 2, the main component is polypropylene, and the following (1)

It is said that by molding a polypropylene resin composition having the characteristics (4) to (4), various large molded articles excellent in appearance and rigidity can be obtained. (1) 230. C, 2. Melt flow rate (MFR) measured under 16kg load is 0.01 ~ 5g / l0min, (2) Intrinsic viscosity measured in decalin at 135 ° C [η] 8 ~: 13dl / The content of high molecular weight polypropylene in g is 15-50% by weight, (3) the number of dies is 3000/450 cm2, and (4) measured by gel permeation chromatography (GPC). High molecular weight distribution Mw / Mn of 6 to 20 and Mz / Mw of 3.5 or more, large molded products with high melt tension, excellent moldability, excellent rigidity, good appearance and resistance to deformation Polypropylene resin compositions that can be obtained efficiently by high-speed molding are disclosed.

[0010] Further, Patent Document 3 discloses that a thermoplastic polymer (A) and ultrahigh molecular weight polyolefin (b-1) having an intrinsic viscosity [77] of 10 to 40 dl / g are 10 to 50% by weight [r? ] Is 0.:!~5dl/g Polyolefin (b-2) 90-50% by weight [The total of (b-1) and (b-2) is 100% by weight. A thermoplastic polymer (B) having a weight ratio [(A) / (B)] of 95/5 to 60/40. By foaming the composition, a foamed molded article of a thermoplastic polymer having a high foaming ratio of 2 times or more, a fine and uniform cell size, and excellent extrusion stability is disclosed.

[0011] In Patent Document 4, a supercritical inert gas, which is a foaming agent, is melted in an extruder by melting a resin composition composed of a thermoplastic resin and a fluoroalkane ester of an aliphatic carboxylic acid. Added to form a completely compatible state of the thermoplastic resin composition and the inert gas. In the gas dissolution process, in the extruder, maintain a pressure above the critical pressure of the inert gas as the blowing agent. In the cooling process that lowers the temperature of the molten resin while holding it, in a die heated above the glass transition temperature of the resin, the pressure is released from the pressure above the critical pressure of the inert gas to the atmospheric pressure. A nucleation step for generating cell nuclei, and a method for producing a thermoplastic resin foam, wherein the foam is cooled to a glass transition temperature or a crystallization temperature of the thermoplastic resin or lower to control the cell diameter. Is disclosed.

Patent Document 1: Japanese Patent Application Laid-Open No. 07-173317

Patent Document 2: W〇99Z07752 Publication

Patent Document 3: Japanese Patent Application Laid-Open No. 2004-217755

Patent Document 4: Japanese Patent Laid-Open No. 10-175248

Disclosure of the invention

Problems to be solved by the invention

[0012] However, the invention described in Patent Document 1 has a problem that it is not suitable for continuous mass production because of the large number of steps including a molding step, a crosslinking step, and a foaming step. In recent years, recycling of plastic molded products has been required due to environmental problems, etc., but melt re-pelletization etc. in the process of recycling the polyolefin resin composition used in such a method. By passing through the process of giving a heat history, decomposition of the cross-linked product and graph product occurs relatively easily, so the melting characteristics necessary for foaming cannot be maintained, and the recyclability is poor. It was.

[0013] In addition, in the inventions disclosed in Patent Document 2 and Patent Document 3, foams (cells) of the foam are uniformly dispersed because a foam with a relatively low expansion ratio of about 5 times can be easily obtained. Although it is a foam, sufficient heat insulating performance has not been obtained yet. For this reason, in order to obtain even better heat insulation performance, it is conceivable to increase the expansion ratio to 10 times or more. However, if the expansion ratio is 10 times or more, it is difficult to obtain a foam having a uniform and fine cell structure. However, there was a problem that it was impossible to obtain a proper heat insulation performance.

[0014] In the invention disclosed in Patent Document 4, in the examples, polystyrene is mainly used as a thermoplastic resin. Compared to amorphous polystyrene, a polyolefin resin having crystallinity is foamed. In general, the resin composition at the time of foaming is influenced by the characteristics of the crystalline resin that the melt viscosity and melt tension drop rapidly due to crystal melting. There is a problem that the viscosity and melt tension of the product are significantly reduced, and bubbles (cells) cannot be sufficiently grown and bubbles are broken. In other words, since the cells could not grow sufficiently, it was difficult to obtain a foam having a uniform and fine cell structure at a high expansion ratio of 10 times or more.

[0015] In particular, when the foams of Patent Documents 2 and 3 are used as a heat insulating material for building materials, a high expansion ratio of 10 times or more cannot be obtained. Inconvenience occurs when doing so. In other words, because of its low expansion ratio, increasing the thickness of the heat insulating material increases the weight of the heat insulating material, and in order to improve the heat insulating performance as a member, the total weight of the member and the cost of raw materials increase. This is not realistic. In addition, if an average cell diameter of 200 zm or less, more preferably 100 zm or less cannot be obtained, the effect of gas convection inside the cell, which is one of the factors that deteriorate the heat insulation performance, is greatly increased to a level that cannot be ignored. This is not preferable. In other words, it did not fully meet the unique requirements of a building insulation material that is lightweight and exhibits stable thermal performance.

[0016] Therefore, in view of the above problems, the object of the present invention is to have excellent extrusion foamability, excellent heat insulation performance, recyclability, low cost and stable continuous production. An object of the present invention is to provide a foam board for a heat insulating building material made of a polyolefin resin composition. Means for solving the problem

[0017] The present invention has been intensively researched and developed to achieve the above object. As a polyolefin resin containing a polypropylene resin, a polyolefin resin containing a linear polypropylene resin having a specific range of melt tension is used. By blowing and extruding the resin composition with a foaming agent containing at least carbon dioxide in a supercritical state, preferably under specific conditions, an unprecedented foam board for heat insulating building materials having a foaming ratio of 10 times or more can be obtained. As a result, the present invention has been achieved.

[0018] In summary, the present invention has the gist characterized by the following.

(1) A polyolefin resin composition containing a linear polypropylene resin having a melt tension of 5 to 30 g at 230 ° C is used with a foaming agent containing at least carbon dioxide in a supercritical state, and the expansion ratio is 10 A foam board for heat-insulating building materials, characterized by being foamed more than twice. (2) The foam board for heat-insulating building materials according to (1) above, having an average cell diameter of 200 μm or less and a uniform cell diameter distribution with a cell diameter distribution coefficient of 30% or less.

(3) A linear polypropylene resin power having a melt tension of 5 to 30 g at 230 ° C. 50% by mass or more in the polyolefin resin composition described in (1) or (2) above Foam board for heat insulating building materials.

(4) The foam board for a heat insulating building material according to (1) to (3) above, which has a thermal conductivity power of 20 to 40 mW / mK measured according to JIS_A1412.

(5) The foam board for heat-insulating building materials according to (1) to (4) above, which has a thermal conductivity of 20 to 37 mW / mK measured according to JIS-A1412.

(6) A polyolefin resin composition containing a linear polypropylene resin having a melt tension of 5 to 30 g at 230 ° C, using a foaming device having an extruder and a die attached to the tip. And a foaming agent containing at least carbon dioxide in a supercritical state are melt-extruded under a temperature condition of 160 to 250 ° C, and the resin pressure immediately at the die opening is released into the atmosphere at 6 to 20 MPa to perform extrusion foaming. A method for producing a foam board for heat-insulating building materials.

(7) The method for producing a foam board for heat-insulating building materials according to (6), wherein the resin pressure in the immediate vicinity of the die opening is 7 to 15 MPa, and the foam is extruded and foamed.

(8) Extruder force The method for producing a foam board for heat-insulating building materials according to (6) or (7) above, wherein the extrusion discharge amount is 1 to 1000 kg / hr.

The invention's effect

[0019] According to the present invention, a heat insulating building material of a polyolefin resin composition that has excellent extrusion foamability, excellent heat insulation performance, is recyclable, and can be stably produced at low cost. A foam board is provided.

BEST MODE FOR CARRYING OUT THE INVENTION

[0020] The polyolefin resin in the polyolefin resin composition of the present invention contains a polypropylene resin, and the polypropylene resin essentially has a melt tension (MT) at 230 ° C of 5 to 30 g. Here, the melt tension can be determined by using a caprograph, with a measurement temperature of 230 ° C, an extrusion speed of 10 mm / min, and a take-up speed of 3. lm / min. If the melt tension is less than 5g, cell breakage will occur at the time of foaming. In other words, the melt tension is too high, the cell membrane is prevented from growing, and sufficient cell growth is not performed during foaming, making it difficult to obtain a foam having a sufficient foaming ratio of 10 times or more. Les. The melt tension is preferably 6.5 to 20 g, more preferably 7.5 to 10 g.

Furthermore, the polypropylene resin preferably satisfies the following formula (I) between the melt tension at 230 ° C. and the melt flow rate (MFR) at 230 ° C.

Log (MT)> _ 1. 331og (MFR) + 1.2 (I)

[0022] When the melt tension and MFR of the polypropylene resin contained in the polyolefin resin composition in the present invention satisfy the above formula (1), the melt fluidity of the resin is simultaneously increased with respect to the increase of the melt tension. The resin pressure at the time of extrusion during foaming is appropriately maintained, and the cell membrane is sufficiently stretched during foaming, so that a high-magnification foam can be easily obtained.

[0023] The polyolefin resin composition of the present invention may contain other resins in addition to the polypropylene resin having the above specific characteristics. However, even when other resins are included, the polypropylene resin having the specific melt tension, and preferably the specific MFR, is preferably 50% by mass or more, particularly in the polyolefin resin composition of the present invention. Is preferably contained in an amount of 80% by mass or more in order to satisfactorily achieve the object of the present invention. If the content of the polypropylene resin in the mixed resin is less than 50% by mass, the resulting foam may have insufficient mechanical strength and heat resistance.

[0024] Examples of the other resin contained in the polyolefin resin composition of the present invention include, for example, polyethylene resin, propylene homopolymer, propylene and one other than propylene copolymerizable with propylene. And a copolymer with olefin. The α-olefin is not particularly limited, but for example, ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1— Otaten etc. are listed. These other resins may be used alone or in combination of two or more. Among these other resins, among others, extrusion foamability and properties of the obtained foam From the viewpoint of excellent performance, a propylene homopolymer having a relatively large molecular weight, a copolymer of propylene and ethylene mainly composed of propylene, and a mixed resin of polypropylene resin and polyethylene resin are preferably used.

[0025] The polypropylene resin having the specific characteristics and the other resins used together with the polypropylene resin contained in the polyolefin resin composition of the present invention are substantially linear. It is preferable that In the present invention, the term “linear” means that each molecular chain of the propylene polymer (propylene polymer) constituting the polypropylene resin is a component of the propylene polymer (propylene polymer). This means that the unit propylene monomer and the olefin monomer copolymerizable therewith are practically an aggregate of those polymerized in a single string. As a result, there is virtually no cross-linking structure using methods such as chemical cross-linking, electron beam cross-linking, or graft structures such as long-chain branching. It is also suitable for repeated thermal histories received in the process of re-pelletizing and the like because the molecular structure hardly deteriorates.

[0026] The foam board for building material in the present invention is foamed using a foaming agent containing at least carbon dioxide in a supercritical state. Such foaming is preferably performed using 4 to 20 parts by mass, particularly preferably 5 to 15 parts by mass of a foaming agent containing carbon dioxide in a supercritical state with respect to 100 parts by mass of the polyolefin resin composition. is there. If the amount of carbon dioxide used is less than 4 parts by mass, the foaming ratio is liable to decrease. On the other hand, if it exceeds 20 parts by mass, large voids due to excess carbon dioxide are likely to occur in the foam.

[0027] The polyolefin resin composition used in the present invention contains a polypropylene resin having the above-mentioned specific physical properties, but the polyolefin resin composition does not impair achievement of the object of the present invention. If necessary, phenolic, phosphorus, amine, sulfur-based antioxidants (anti-aging agents), heat stabilizers, light stabilizers, UV absorbers, phosphorus-based, nitrogen-based, halogen-based, One or more of various additives such as antimony flame retardants, lubricants, metal damage inhibitors, antistatic agents, fillers, colorants, cell nucleating agents, crystal nucleating agents, etc. may be added. .

[0028] The cell nucleating agent is not particularly limited, but talc, calcium carbonate. And clay, kaolin, mica, magnesium oxide, zinc oxide, carbon black, glass, quartz, silica, alumina, novaquilite, hydrated alumina, iron, iron oxide, silicon dioxide, titanium oxide and the like.

[0029] The crystal nucleating agent is not particularly limited, and generally includes a rosin-based crystal nucleating agent, a sorbitol-based crystal nucleating agent, and a phosphate ester-based crystal nucleating agent. It is The rosin-based crystal nucleating agent is not particularly limited as long as it is a rosin-based resin, and examples thereof include dibenzylidene sorbitol (DBS) manufactured by Shin Nippon Rika Co., Ltd. The phosphoric acid ester salt nucleating agent is not particularly limited, and examples thereof include NA_11 manufactured by Asahi Denka Kogyo Co., Ltd. These crystal nucleating agents may be used alone or in combination.

[0030] A foam board for a heat-insulating building material of the present invention includes a linear polypropylene resin having the above-mentioned specific physical properties using a foaming apparatus having an extruder and a die attached to the tip. The resin composition is mixed with a blowing agent containing at least carbon dioxide in a supercritical state, and is manufactured by melt extrusion at a temperature of 160 to 250 ° C. When the melt extrusion temperature is less than 160 ° C, the dissolution and diffusion of supercritical carbon dioxide into the resin is poor, and conversely, when it exceeds 250 ° C, deterioration of the polypropylene resin such as molecular chain breakage due to heat begins to occur. Therefore, it is not preferable. Further, the resin pressure (pressure loss) in the immediate vicinity of the die opening in the extruder is preferably 6 to 20 MPa, released into the atmosphere, and extruded and foamed. Among them, the pressure loss is more preferably 7 to 15 MPa, and most preferably 9 to 15 MPa. If the pressure loss is less than 6 MPa, the supercritical carbon dioxide dissolved in the polyolefin resin composition is easily vaporized inside the extruder and inside the die, and foaming occurs inside the apparatus, and It is not preferable because it causes foaming, excessive growth, reduction of expansion ratio, remarkably low appearance and appearance. On the other hand, if the pressure loss exceeds 20 MPa, large shearing tends to be applied to the cell during cell formation in foaming, and cell foaming and cell structure non-uniformity are undesirable. Such imperfect cell structure is a major obstacle to exhibiting sufficient thermal performance as a foam board for heat insulating building materials.

[0031] The extrusion discharge rate in the extruder is preferably 1 to 1000 kg / hr. In particular, the amount of extrusion discharge depends on the specifications of the extruder. In general, l to 50 kg / hr is preferable. In a type having a relatively large screw diameter, about 20 to 1000 kg / hr is preferable. If the discharge rate is too large or too small, it will be difficult to maintain a pressure loss suitable for foaming at the die part, and it will not be possible to obtain a foam with a sufficient magnification, or the cells may break. I'll be relaxed.

[0032] For the extruder to be used, two screws having a screw diameter (D) of preferably 40 to 80 mm and a screw length of (L) (LZD) of preferably 15 to 40 are used. A tandem type extruder configured on the basis of being combined in series is preferable. By using a tandem type extruder, the resin pressure loss condition and the discharge amount of the die part suitable for foaming can be controlled independently by the number of rotations of each screw, and the above-described polyolefin resin composition of the present invention can be controlled. The foam board having excellent characteristics and excellent characteristics can be manufactured.

[0033] The shape of the die used in the extruder is not limited, but the number, shape, and thickness of the opening are designed so that the pressure loss per opening is 6 to 20 MPa as described above. For example, a slit die or a multi-hole die is preferable. By selecting a die that satisfies these conditions, it is possible to obtain a foam board for a heat-insulating building material that exhibits sufficient thermal performance.

[0034] In addition, from the viewpoint of the appearance of the molded product after foaming and the ease of adjusting the shape, the diameter of the opening in the extruder that is preferably circular is 0.:!-2. Omm is preferred, and 0 · 3 to 0 · 7mm is more preferred. It is preferable that a plurality of openings are provided on the front surface of the die, the die depth being preferably 0.1 to 10 mm.

[0035] If the diameter is less than 0.1 mm, the strand diameter of the foam structure is too small, and it is easy to tear off when taken. 2. If the diameter exceeds Omm, the strand diameter is too large. This is preferable because post-molding of the shape becomes difficult. Also, slit-shaped dies having a width of 0.:! To 2.0 mm and a length of 0.1 to 1000 mm can be used.

[0036] As a specific example of the method for producing a foam board for heat-insulating building materials of the present invention, the above polyolefin resin composition is used, for example, in a carbon dioxide supply line having a supercritical carbon dioxide supply capability in the middle of a cylinder barrel. Using the provided extrusion molding machine, the foamable polyolefin resin composition is heated to a predetermined temperature and uniformly melted and kneaded, and then a predetermined amount of supercritical carbon dioxide is supplied from a supply line to form a board shape. Foam by extruding into A body board is manufactured.

[0037] Furthermore, if necessary, the shape and size may be adjusted using a cutting machine, a sandwiching conveyor, or the like in order to adjust the product form of the foam board for heat insulating building materials.

[0038] Further, if necessary, for example, a sheet-like material such as an aluminum sheet non-woven fabric or leather is bonded to one side or both sides of the foam board as a face material, and the strength, heat resistance, flame retardancy, etc. Various performances may be imparted.

Thus, the foam board for heat-insulating building materials of the present invention can have the cell diameter and cell distribution coefficient described later even when the expansion ratio is 10 times or more, and further 15 times or more, particularly Even a foaming ratio of 20 times or more is preferable because it has the cell diameter and cell distribution coefficient and sufficient member thermal performance. Further, it is preferable to use a high expansion ratio because the specific gravity of the foam can be reduced and the cost of the raw materials used can be reduced. On the other hand, if the expansion ratio is too high, the mechanical strength of the foam is reduced. For example, when used as a building material, the foam tends to be damaged by external addition during construction. Nare ,. Therefore, the expansion ratio is preferably 100 times or less, particularly 50 times or less.

[0040] In addition, the foam board for heat-insulating building materials of the present invention preferably has an average cell diameter of 200 µm or less and 150 µm or less, and more preferably 50 to 100 / im. In addition, the cell diameter distribution coefficient can be 30% or less, more preferably 25% or less, and particularly 20% or less. When the average cell diameter is 200 / m or less and the cell diameter distribution coefficient is 30% or less, the heat insulation performance is particularly excellent when used as a building material.

[0041] In the present invention, the average cell diameter means that the foam is cut into small test pieces, and the cross-sectional area is randomly determined from an image observed with an electron microscope (SEM) at a magnification of 50 times. The average cell diameter can be obtained by calculating the average cell diameter using the following formula by drawing 10 straight lines with a length of 2 mm and counting the number of cells on the straight line.

(Average cell diameter μ m) = (2000 X 10) Z (number of cells on 10 straight lines) [0042] Further, in the present invention, the cell diameter distribution coefficient is determined from 10 to 20 pieces from an image observed by cutting the foam into test pieces and observing the cross-sectional area with an electron microscope (SEM) at a magnification of 50 times. The average cell diameter and the standard deviation of the cell diameters are calculated, and the cell diameter distribution coefficient can be obtained by the following formula based on these values.

(Cell system distribution coefficient%) = (Standard deviation of cell diameter) / (Average value of cell diameter) X 100

[0043] Further, the foam board for heat-insulating building materials of the present invention has a thermal conductivity of 20 to 40 mWZmK measured in accordance with JIS-A1412, and can obtain a foam board for heat-insulating building materials having suitable heat insulation properties. it can. Furthermore, the thermal conductivity is more preferably 20 to 37 mW / mK. When the thermal conductivity exceeds 40 mW / mK, the thermal insulation performance is not only inferior, but the thermal insulation value is 0.9 or more to obtain a thermal resistance value of 0.9 or more, which is a preferable thermal performance evaluation standard for a thermal insulation construction board. Therefore, when this is used as, for example, a heat insulating material for floors, it becomes larger than the size of the wooden frame of the floor, which may cause problems during construction, which is not preferable.

Example

[0044] In order to describe the present invention in more detail, examples will be given below, but the present invention is not limited to these examples.

[0045] Example 1

Polypropylene resin A with MFR force 3 at 230 ° C of 3 (g / l0 min) and melt tension at 230 ° C of 7.6 g was supercritical carbon dioxide feeder ( Tandem type single shaft equipped with carbon dioxide supply line from C 02—3) and equipped with die 1 (8 x 48-row multi-hole die with an opening diameter of 0.5 mm) at the second stage tip Supply to an extruder (KGT-50-65 manufactured by Rikita Co., Ltd.), set the carbon dioxide supply rate to 1.2 kgZ hours, and contain 6 parts by mass with respect to 100 parts by mass of polypropylene resin. The amount of extrusion is adjusted by the screw speed of the first-stage extruder, and the resin pressure at the first stage of the die is adjusted by the screw speed of the second-stage extruder so that the pressure is 8.7 MPa. A foam board 1 for a heat insulating building material of a polyolefin resin composition was obtained. [0046] Example 2

The carbon dioxide supply rate is set to 1.5 kg / hour, the extrusion amount is adjusted with the screw speed of the first-stage extruder so that 7.5 mass parts is contained per 100 mass parts of the polypropylene resin A, and A polyolefin resin composition was prepared in the same manner as in Example 1 except that the resin pressure at the die 1 site was adjusted to 8.9 MPa with the screw rotation speed of the second-stage extruder and extruded and foamed. The foam board 2 for heat-insulating building materials was obtained.

[0047] Example 3

Set the carbon dioxide supply amount to 1.8 kgZ hours, adjust the extrusion amount with the screw speed of the first-stage extruder so that it is 9 parts by mass with respect to 100 parts by mass of polypropylene resin A, and dice 1 Insulation of the polyolefin resin composition is carried out in the same manner as in Example 1 except that the resin pressure at the part is adjusted to 9.2 MPa with the screw speed of the second-stage extruder and extruded and foamed. A foam board 3 for building materials was obtained.

[0048] Example 4

The carbon dioxide supply rate is set at 1.9 kg / hour, the extrusion rate is adjusted with the screw speed of the first-stage extruder so as to contain 6 parts by mass with respect to 100 parts by mass of the polypropylene resin A, and the die The polyolefin resin composition was prepared in the same manner as in Example 1 except that the resin pressure at one part was adjusted to the screw rotation speed of the second stage extruder so that the pressure was 8.8 MPa, and extrusion foaming was performed. A foam board 4 for heat insulating building materials was obtained.

[0049] Example 5

Set the carbon dioxide supply rate to 1.2 kg / hour, and the extrusion rate in the first stage to contain 6 parts by mass with respect to 100 parts by mass of the polypropylene resin B having a melt tension of 8.5 g at 230 ° C. Same as in Example 1 except that the pressure was adjusted by the screw speed of the machine and the screw speed of the second stage extruder was adjusted so that the resin pressure at the die A part was 8.8 MPa. The foamed board 5 for a heat insulating building material of the polyolefin resin composition was obtained by carrying out the above.

[0050] Example 6

A foamed board 6 for a heat-insulating building material of a polyolefin resin composition was obtained in the same manner as in Example 1 except that the resin pressure at 1 part of the die was 6.5 MPa. [0051] Example 7

As the polyolefin resin composition, polypropylene resin C (homopolypropylene resin A) having 45 parts by mass of polypropylene resin A, MFR at 230 ° C of 6 g / 10 min, and melt tension at 230 ° C of 1/8 g. Resin) A foamed board 7 for a heat insulating building material of a polyolefin resin composition was obtained in the same manner as in Example 1 except that the resin pressure was 55 parts by mass and the resin pressure at one part of the die was 8.65 MPa.

[0052] Example 8

A foamed board 8 for a heat-insulating building material of a polyolefin resin composition was obtained in the same manner as in Example 1 except that the resin pressure at 1 part of the die was 16. IMPa.

[0053] Comparative Example 1

The same tandem type single-screw extruder used in Example 1 for polypropylene resin C (homopolypropylene resin) with MFR force of S6gZlO at 230 ° C and melt tension of 1.8g at 230 ° C Set the carbon dioxide supply rate to 1.2 kg / hour, and adjust the extrusion amount with the screw speed of the first-stage extruder so that it contains 6 parts by mass with respect to 100 parts by mass of the polypropylene resin. Then, the foam pressure board 6 for the heat insulating building material of the polypropylene resin composition was obtained by adjusting the screw rotation speed of the second stage extruder so that the resin pressure at the die 1 site was 4.5 MPa and by extrusion foaming. .

[0054] Comparative Example 2

230. MFR force in C S3. 3g / 10min, 230. Polypropylene resin A having a melt tension force of 7.6 g in C is supplied to the same tandem single screw extruder used in Example 1, and the carbon dioxide supply rate is 1.2 KG / hour. Adjust the amount of extrusion so that it contains 6 parts by mass with respect to 100 parts by mass with the screw speed of the first stage extruder, and dice 2 (8 x 48 rows of multi-hole dies with an opening diameter of 0.8 mm). ) The resin pressure at the site was adjusted to 5. IMPa by adjusting the screw speed of the second-stage extruder, and extrusion foaming was performed to obtain a foamed board 7 for heat-insulating building materials of a polypropylene resin composition.

[0055] Comparative Example 3

The performance of a commercially available polyethylene foam board manufactured by the bead method with an expansion ratio of 90 times was evaluated. The performance ((a) density, (a) of the polyolefin (polypropylene) resin foam obtained in Examples 1 to 5 and Comparative Examples 1 and 2 and Comparative Example 3 in Comparative Example 3 b) Compressive strength, (c) Average cell diameter, (d) Thermal conductivity, (e) Cell diameter distribution coefficient) were evaluated by the following methods.

(a) Density: The obtained foam is cut into test pieces of 20 X 20 X 2.5 (cm), the weight and length of each side are measured, and the foam density is obtained according to the following formula. It was.

(Foam density G / L) = (Foam weight G) / (Foam volume L)

(b) Compressive strength · The 25% compression hardness (kPa) of the foam was measured according to 'JISK-6767 (polyethylene foam test method).

(c) Average cell diameter '·' The foam was cut into test pieces, and the cross-sectional area was observed with an electron microscope (SEM) at a magnification of 50 times using SEM Superscan 220 manufactured by Shimadzu Corporation. The average cell diameter was calculated by the following formula by drawing 10 straight lines with a length of 2 mm at random from the image and counting the number of cells on the straight line.

(Average cell diameter τα) = (2000 X 10) / (number of cells on 10 straight lines)

(d) Thermal conductivity ··· The foam obtained was cut into 20 X 20 X 2 (cm) test pieces according to 'JISA-1412', and the thermal conductivity measuring device HC— The thermal conductivity was measured using 074.

(e) Cell diameter distribution coefficient '· · The resulting foam is cut into test pieces, and the cross-sectional area is observed with a 50x magnification using Shimadzu Corporation SEM Superscan 220. The average value of the cell diameter of 20 cells and the standard deviation of the cell diameter were calculated. Based on these values, the cell diameter distribution coefficient was obtained by the following formula. (Cell diameter distribution coefficient) = (Standard deviation of cell diameter) / (Average value of cell diameter)

(f) Melt tension: Determined using a Capillograph 1C (manufactured by Toyo Seiki Co., Ltd.) at a measurement temperature of 230 ° C, an extrusion speed of 10 mmZmin, and a take-up speed of 3. lmZ. For the measurement, an orifice with a length of 8 mm and a diameter of 2.095 mm was used.

(g) Foam magnification ratio “·” It was determined according to the following formula from the specific gravity of the resin and the measurement result of the density obtained in (a).

(Foaming ratio) = (Specific gravity of resin) / (Density of foam) Table 1 summarizes the blending composition, extrusion conditions, and physical properties of the obtained foam used in the present invention.

[table 1]

Table 2

Industrial applicability

[0059] The foam of the polyolefin resin composition of the present invention has a variety of excellent performance and cost. It can be widely used mainly for heat insulating building materials, automotive parts, and packaging cushioning materials. It should be noted that the entire contents of the Japanese Patent Application 2005-192375, filed on June 30, 2005, and the claims, drawings, and abstract are cited herein, and the description of the present invention is disclosed. It is included as an indication.

Claims

The scope of the claims

[1] A polyolefin resin composition containing a linear polypropylene resin having a melt tension of 5 to 30 g at 230 ° C. is used with a blowing agent containing at least carbon dioxide in a supercritical state, and the expansion ratio is Foam board for heat-insulating building materials, characterized by being foamed 10 times or more

[2] The foam board for heat-insulating building materials according to claim 1, wherein the foamed board has a uniform cell diameter distribution with an average cell diameter of 200 μm or less and a cell diameter distribution coefficient of 30% or less.

[3] The heat insulating building material according to claim 1 or 2, wherein a linear polypropylene resin having a melt tension at 230 ° C of 5 to 30 g is contained in the polyolefin resin composition in an amount of 50% by mass or more. Foam board.

[4] The thermal conductivity power measured in accordance with JIS—A1412 is 20-40 mW / mK.

The foam board for heat-insulating building materials according to any one of: to!

[5] The thermal conductivity power measured in accordance with JIS-A1412 is 20 to 37 mW / mK.

The foam board for heat-insulating building materials according to any one of 1 to 4.

[6] A polyolefin resin composition containing a linear polypropylene resin having a melt tension of 5 to 30 g at 230 ° C., using a foaming apparatus having an extruder and a die attached to the tip. And a foaming agent containing at least carbon dioxide in a supercritical state are melt-extruded under a temperature condition of 160 to 250 ° C, and are extruded and foamed to the atmosphere at a resin pressure in the immediate vicinity of the die opening of 6 to 20 MPa. The manufacturing method of the foam board for heat insulation building materials.

[7] The method for producing a foam board for a heat-insulating building material according to claim 6, wherein the resin pressure in the immediate vicinity of the die opening is 7 to 15 MPa, and the foam is extruded and foamed.

[8] The method for producing a foam board for heat-insulating building materials according to [6] or [7], wherein the extruder is a tandem type extruder having an extrusion discharge rate of 1 to 1000 kg / hr.