JPH0321335B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composite heat insulating material used as a lining material for the main body and door of a refrigerator. The composite electric heating material of the present invention is a heat insulating material having a structure in which urethane foam and a sheet of polyolefin resin or styrene resin are firmly adhered. The main body and doors of the refrigerator are coated with acrylonitrile, a styrene-based resin, to prevent rust on the baked-on stainless steel and steel plate structural base material (outer frame) and to form shelves.
Butadiene-styrene copolymer (commonly known as "ABS")
The inner lining material is obtained by vacuum forming a sheet, pressure forming, or forming using a combination of vacuum and pressure forming (hereinafter, these forming methods are collectively referred to as differential pressure forming). In addition, attempts have been made to use polypropylene lining materials with excellent surface gloss and low water absorption in place of ABS lining materials. In order to improve the heat insulation properties of refrigerators, it has been proposed to interpose urethane foam between the baked-on stainless steel plate, which is the structural base material of the refrigerator, and the regular lining material, but it is difficult to obtain such a laminated structure. has the following problem. (i) When a polyolefin resin sheet is used as the lining material, the adhesion between the polyolefin resin sheet and the urethane foam, which is a heat insulator, is poor. (ii) Before performing differential pressure molding on ABS or polyolefin sheets, it is necessary to wipe off dust adhering to the sheet surface with a cloth, etc. In particular, this step is essential because polypropylene, which does not have polar groups, is more susceptible to dust and dirt than ABS. Problem (i) above is solved by laminating the lining material and urethane foam, which are pre-formed by differential pressure, using liquid acrylic adhesive or epoxy adhesive, and then applying adhesive to the inside of the laminated material. This can be solved by inserting and press-bonding it into a baked-on stainless steel structural base material (formwork) that has been coated, but a method that involves multiple steps will be costly. Therefore, as shown in FIG. 1, a foamable urethane solution 4 is injected into the cavity 3 formed by the formwork 1 and the lining material 2, and then foamed and cured to form the formwork 1 and the urethane foam. An on-site method of manufacturing a multi-layered structure in which the body 4' and the lining 2 are integrated is preferred. Problem (ii) above can be solved by using a sheet made by kneading an antistatic agent into the resin of the sheet material, or by applying an antistatic agent liquid to the front and back layers of the sheet, or at least to the surface that will be bonded to the urethane. This problem can be solved by using a dried sheet. However, with the above-mentioned method of kneading an antistatic agent into the resin, the sheet must be stored for 30 to 50 days after forming the sheet before the antistatic function is imparted to the sheet surface. I can't. On the other hand, it is necessary to take care to ensure that the sheet storage period is not affected by dust, which is not a good idea. Further, the antistatic function of the sheet formed by this method is maintained for at most 3 to 6 months after the sheet is formed. The latter method involves applying an antistatic agent solution to the sheet.
Drying has the advantage of imparting an antistatic effect to the sheet in a short period of time. However, this antistatic agent is required to have the following functions. Good adhesion to the sheet. Has stretchability. That is, since the sheet is formed by differential pressure, the antistatic agent is required to have spreadability as well as the sheet. Excellent adhesion to urethane foam. The present inventors have investigated various coated adhesives that have an antistatic function and satisfy the required performance when manufacturing laminated structure insulation materials of urethane foam and ABS or urethane foam and polypropylene using the on-site method. However, it has been confirmed that a specific polymer antistatic agent satisfies the above-mentioned required performance, and the present invention has been achieved. That is, in the present invention, a polyolefin resin or a styrene resin and a urethane foam contain the following component (A).
The present invention provides a composite heat insulating material laminated with an adhesive containing component (B). Adhesive composition: (A) 20-100% by weight of a water-soluble polyimine compound selected from the group consisting of polyethyleneimine, poly(ethyleneimine-urea) and ethyleneimine adducts of polyamine polyamides (B) Nitrogen-containing cationic or Amphoteric polymer 80-0% by weight. In the present invention, the resin for the sheet material includes:
Polyolefin resins such as high density polyethylene, low density polyethylene, polypropylene, ethylene/propylene copolymer, ethylene/propylene/butene copolymer; polystyrene, styrene/butadiene/styrene block copolymer (so-called
Examples include styrenic resins such as SBS), acrylonitrile-butadiene-styrene copolymer (so-called ABS), and high-impact polystyrene (so-called HIPS). These may be used alone or in combination of two or more. A stabilizer, an inorganic filler, a pigment, a rubber, etc. may be added to this resin. These resins are extruded into sheets, and if necessary, the front and/or back surfaces are treated with corona discharge, and the thickness is 0.3 to 4.
It is said to be a sheet for differential pressure molding of mm. Next, as an agent having an antistatic function, the water-soluble polyimine compound of component (A) alone or containing 20% by weight or more (solid content) of component (A), and (B)
A mixture containing up to 80% by weight of the constituent nitrogen atom-containing cationic or amphoteric polymers is used, and the adhesive is used as an aqueous solution with a concentration of 0.5 to 3% by weight. Preferably, component (A) is 20 to 80% by weight and component (B) is
An adhesive comprising a mixture of 80 to 20% by weight is preferred from the viewpoint of antistatic and antiblocking properties. however,
The content of the polyimine compound of component (A) is 85% by weight or more.
When it is 100% by weight, the antistatic function until the resin sheet is thermoformed is not sufficient.
On the surface opposite to the sheet surface to be bonded with urethane,
An antistatic agent consisting of a mixture of 20 to 80% by weight of component (A) and 80 to 20% by weight of component (B), an acrylic polymer antistatic agent of component (B), an anionic surfactant, and a cationic surfactant. surfactants, amphoteric surfactants, nonionic surfactants, such as lauryl aminopropionate sodium salt, stearyltrimethylammonium chloride, 1-hydroxyethyl-2-undecyl-2-imidazoline.
Ethylene oxide adduct, nonylphenol
It is necessary to apply an antistatic agent such as ethylene oxide adduct or lauryl sulfate sodium salt. The above component (A), polyethyleneimine, a copolymer of ethyleneimine and urea [poly(ethyleneimine-urea)], or a polyamine polyamide with ethyleneimine added, is available from BASF in West Germany as Polymin SN, Polymin P, It is sold by Nippon Shokubai Kagaku Kogyo Co., Ltd. under the trade name Epomin P-1000.
This (A) polyimine compound greatly contributes to improving the adhesion with urethane. The nitrogen atom-containing cationic or amphoteric polymer of component (B) is water-soluble and greatly contributes to the anti-blocking and antistatic functions of the sheet.
Such a polymer of component (B) can be produced by polymerizing a quaternized nitrogen-containing monomer or by quaternizing a tertiary nitrogen-containing polymer. Specific examples of nitrogen-containing monomers suitable for the present invention include the following. Here, in each formula, R ¹ is hydrogen or a methyl group,
R ² and R ³ are each a lower alkyl group (especially,
_C1 to _C4 , especially _C1 to _C2 ), ^R4 is a saturated or unsaturated alkyl group or benzyl group having 1 to 22 carbon atoms,
X is a quaternized counteranion of N (e.g. halide (especially chloride)), A has 2 carbon atoms
~6 alkylene group. The chargeable polymer of component (B) consists of these quaternary (amphoterized) nitrogen-containing monomers (b), (d), (d)', (f), (f)'
,(blood),
It can be obtained by homopolymerizing (h)′ and (li), or by copolymerizing these quaternary nitrogen-containing monomers with other vinyl monomers. In addition, tertiary nitrogen-containing monomers
(a), (c), (e), and (g) are homopolymerized or copolymerized with other monomers, and then quaternized with a cationizing agent such as alkyl halide, dimethyl sulfate, or benzyl halide monochloroacetic acid ester. It goes without saying that it can be made to exist in the polymer by amphoteric conversion or amphoteric conversion using an amphoteric agent such as monochloroacetic acid (salt), propanesultone, propiolactone, etc. In the present invention, the polymer of component (B) needs to be water-soluble, but it is not desirable that it be excessively water-soluble. Therefore, this tertiary to quaternary nitrogen-containing polymer is preferably a copolymer with a hydrophobic monomer. Examples of the hydrophobic monomer include styrene or its substituted derivatives in the nucleus or side chain, acrylic or methacrylic acid esters, vinyl halides, and others. Particularly suitable polymers for component (B) in the present invention are as follows.
This is an acrylic polymer made by copolymerizing components (a) to (c). (a) Monomers (a) to (f) 20 to 40% by weight (b)

[In the formula, R ¹ is H or a methyl group, and R ⁵ is a C ₁ to C ₁₈ alkyl group]

(c) 0 to 20% by weight of other hydrophobic vinyl monomers. The most suitable acrylic polymer as component (B) in the present invention is one in which the monomer (a) is the above-mentioned monomer (f). This acrylic polymer is manufactured by Mitsubishi Yuka Fine Co., Ltd.
ST-1000, ST-1100, ST-1300, ST- from Co., Ltd.
It is sold under 3000 product names. Heat resistance and water resistance can be imparted to the antistatic film by further blending an epichlorohydrin adduct of polyamine polyamide with these components (A) and (B). This polyamine polyamide-epichlorohydrin adduct is a water-soluble, cationic thermosetting resin obtained by reacting a polyamide made from a saturated dibasic carboxylic acid having 3 to 10 carbon atoms and a polyalkylene polyamine with epichlorohydrin. It is sold under the trade name Kamain-557H by Deitzk Harkyures and AF-100 by Arakawa Forestry Chemical Industry Co., Ltd. Details of this resin are described in Japanese Patent Publication No. 3547/1983. Specific examples of C ₃ to _{C 10} saturated dibasic carboxylic acids are C ₄ to C ₈ dicarboxylic acids, especially adivic acid, and specific examples of polyalkylene polyamines are polyethylene polyamines, especially ethylene diamine, diethylene triamine and triethylene tetramine, especially Diethylenetriamine. The molar ratio of polyalkylene polyamine to dibasic acid in the polyamide production reaction is usually about 0.9:1 to 1.2:1. The reaction of the polyamine polyamide with epichlorohydrin typically uses from about 0.5 to about 1.8 moles of epichlorohydrin for each secondary amine group in the polyamide. Aqueous solutions 2a and 2c of adhesives having an antistatic function containing these components (A) and (B) are applied by rolling, brushing, spraying, etc. to at least the back side of the sheet 2b that is to be bonded to the urethane. 1.0
g/m ² (solid content) and dried (see Figure 2). The antistatic resin film 2a obtained in this way,
The resin sheet provided with 2c on the front and back surfaces or on the back side to be bonded to urethane is subjected to normal differential pressure molding and shaped into a shape suitable as a refrigerator lining material. This shaped sheet 2 is perforated with a urethane solution 4 injection port 5 if necessary, and is inserted into a stainless steel or aluminum formwork 1, which is the outer structural base material of the refrigerator, as shown in Fig. 1. . Next, from the injection port 5, a two-component foaming urethane solution is poured into the cavity 4 formed by the mold 1 and the lining material 2.
The polyurethane foam 4' and the lining material 2 are injected into the lining material 2 and are injected into the lining material 2 to form a multi-layered lining material having a heat insulating property. Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that parts and percentages in the examples are based on weight. Example 1 of sheet production Example 1 (i) Resin used for glossy layer: A crystalline propylene homopolymer with an MFR of 2.0 g/10 minutes and a residual amount of 99% by weight after extraction with boiling heptane was used. (ii) Resin used for deep drawing layer: ethylene content 5% by weight, MFR 0.5g/10 minutes, boiling heptane extraction residue
98% by weight crystalline propylene-ethylene block copolymer 40% by weight, density 0.950g/cm ² ,
A composition consisting of 40% by weight of polyethylene with an MFR of 0.6g/10 minutes and 20% by weight of talc having a particle size of 1.5μ was kneaded in an extruder, extruded into a strand, and cut into pellets. The resin pellets for the deep drawing layer in (ii) above are fed to a two-layer multi-manifold die with a width of 700 mm at 230°C using an extruder with a diameter of 90 mm, and the resin for the glossy layer in (i) is fed into an extruder with a diameter of 40 mm. was used to feed the same die at 230. The temperature of the die was 230°C. The molten sheet extruded from the die was sequentially cooled and solidified using three rolls each having a width of 700 mm, and then subjected to corona discharge treatment to obtain a sheet for vacuum forming. The temperature of the rolls is 80℃, 95℃, and 100℃ from the roll closest to the die.
The rotation speed of the roll was 1.5 m/min. The total sheet thickness is 1.6mm, and the gloss layer is 0.25mm.
mm, and the deep drawing layer was 1.35 mm. Example 2 Polypropylene “Mitsubishi Noblen” manufactured by Mitsubishi Yuka Co., Ltd.
MA-8" (trade name) was extruded into a sheet at 230°C, and then subjected to corona discharge treatment to obtain a sheet with a wall thickness of 1.6 mm. Example 3 ABS resin "Toughflex 157" manufactured by Mitsubishi Monsanto Chemical Co., Ltd. Product name) is extruded into a sheet at 220℃,
A sheet with a wall thickness of 1.6 mm was obtained. Example 4 Polypropylene “Mitsubishi Noblen MH-6” 35 parts high-density polyethylene “Yukalon Hard EY-40”
25 parts Styrene-butadiene-styrene copolymer 12 parts Talc 24 parts Titanium oxide 4 parts A sheet with a thickness of 1.6 mm was obtained in the same manner as in Example 2, except that the above resin composition was used in place of polypropylene. Example 5 (i) Resin used for the glossy layer: A crystalline propylene homopolymer with an MFR of 2.0 g/10 minutes and a residual amount of 99% by weight after extraction with boiling heptane was used. (ii) Resin used for deep drawing layer: Polypropylene “Mitsubishi Noblen MH-6”
25 parts high-density polyethylene “Yukalon Hard EY-40”
15 parts Styrene-butadiene-styrene copolymer 12 parts Calcium carbonate 40 parts Polystyrene 8 parts The resin for the deep drawing layer (ii) above is supplied to a 3-layer multi-manifold die with a width of 700 mm at 230°C using an extruder with a diameter of 90 mm. In addition, the glossy layer resin (i) was supplied to the same die at 230°C using an extruder with a diameter of 40 mm. The temperature of the die was 230°C. The molten sheet extruded from the die was sequentially cooled and solidified using three rolls with a width of 700 mm, and then subjected to corona discharge treatment to obtain a sheet for vacuum forming. The temperatures of the rolls were 80°C, 95°C, and 100°C starting from the roll closest to the die, and the rotational speed of the rolls was 1.5 m/min. The total thickness of the sheet was 1.6 mm, the glossy layers on the front and back sides were each 0.2 mm, and the deep drawing layer in the middle was 1.2 mm. Production example of acrylic polymer as component (B) N,N-dimethylaminoethyl methacrylate
80 parts (0.5 mol) of methyl methacrylate, 50 parts (0.5 mol) of isopropyl alcohol, and 200 parts of isopropyl alcohol were placed in a four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a dropping funnel, and after purging with nitrogen gas, , 0.9 part of 2'-azobisisobutyronitrile was added as a polymerization initiator, and the polymerization reaction was carried out at 80°C for 4 hours. Next, add 60 parts of monochloroacetic acid soda, and add 80 parts of sodium monochloroacetate.
After reaction (amphomerization) at ℃ for 6 hours, water was added while distilling off isopropyl alcohol to obtain an aqueous solution with a solid content of 35%. This acrylic polymer (hereinafter referred to as "ST") is is included in the molecular chain. Example 1 Both sides of the two-layered sheet obtained in Example 1 were coated with 35% of the acrylic polymer obtained in the above example and 65% of BASF's ethyleneimine adduct "Polymine SN" of polyamine polyamide (solid content ratio). A 1% aqueous solution of the mixed polymer (2) was applied to each of the front and back surfaces at a ratio of 0.3 g/m ² (solid content) and air-dried. The surface specific resistance value of this sheet is 6.5×10 ⁸ Ω・cm
The anti-blocking property was normal. Using a vacuum/pressure forming machine, this sheet is made into approximately 220
It was introduced into a heating furnace set at ℃ and compressed air (5.0Kg/cm ² )
Plug-assisted molding was performed using a combination of pressure and reduced pressure (-600 mmHg). After drilling an injection port in a part of this shaped sheet, this sheet is inserted into a stainless steel frame that is the frame of the refrigerator body, and then the space (cavity) formed by the frame and the shaped sheet is inserted. When a two-component foaming urethane solution "HM-1510" (trade name) manufactured by Polyurethane Kagaku Kasei Co., Ltd. was injected into the space from the injection port, foaming started after 10 seconds, and after 1 minute, the space was filled with urethane. Completely filled with foam.The density of this urethane foam is 0.05g/cm ³
It was hot. After 24 hours, the sheet with the urethane foam adhered to it was cut out, and the adhesion between the urethane foam and the sheet was measured. On the other hand, another sheet (not bonded with urethane) that had been vacuum formed in the same manner as the above sheet was partially cut out, and the specific resistance value and ash adhesion of the sheet surface were examined. The results are shown below. Surface resistivity ^* : 8.8×10 ¹¹ Ω・cm Ash adhesion: No adhesion Adhesion between urethane and sheet: Good (○) Anti-blocking property ^** : Good (○) *Measured at 20℃ and 60% relative humidity ** After overlapping the antistatic agent layer sides of two sheets, a load of 50 g/cm ² was applied and the sheets were left for 24 hours at 20°C and 60% relative humidity to check whether there was any adhesion (blocking). measurement. Good (○): No blocking. Fair (△): Some blocking is observed, but the sheet can be easily peeled off by hand. Bad (x)...Blocking is large. Examples 2 to 4, Comparative Example 1 In Example 1, the mixing ratio of the antistatic agent "Polymine SN" and "ST" to be applied was changed as shown in Table 1, and the surface gloss layer side was charged with A urethane foam/sheet laminated insulation material was obtained in the same manner except that no inhibitor was applied. This laminated heat insulating material was evaluated in the same manner as in Example 1.
The results are shown in Table 1. The evaluation criteria are as follows. Ash adhesion: × - Adhesive even at a height of 5 cm or more △ - Adhesive at a height of 3 to 5 cm ○ - Adhesive or no adhesion at a height of 3 cm or less. Adhesion between urethane and sheet: ××-The sheet and urethane foam peel off without resistance. ×The urethane foam peels off from the sheet interface due to some resistance. Δ-The urethane foam peels off from the base material in some parts. ○ - The urethane foam base material peels off on the entire surface. Examples 5-6, Comparative Examples 2-7 In Example 1, the types of antistatic agent applied to the glossy layer side of the sheet and the antistatic agent applied to the urethane adhesive surface of the sheet were changed as shown in Table 1. A urethane foam/sheet laminated heat insulating material was obtained in the same manner.

【table】

[Table] Examples 7 to 11 Laminated insulation sheets were prepared in the same manner as in Example 5, except that the composition of the antistatic agent (AS agent) applied to the back side of the sheet to be bonded to urethane was changed as follows. Obtained. The physical properties of this product are shown in Table 2.

[Table] * (A) Component
Polymin P = BASF's polyethyleneimine
Epomin P〓1000〓Polyethyleneimine manufactured by Nippon Shokubai Kasei Examples 12 to 15 Examples 12 to 15 The sheets obtained in Examples 2 to 5 above are used instead of the laminated sheet obtained in Example 1 as the sheet for differential pressure molding. A urethane foam/sheet laminated heat insulating material was obtained in the same manner as in Example 5. The physical properties of this product are shown in Table 3. Examples 16 to 18 Laminated heat insulating materials were obtained in the same manner as in Example 15, except that the composition of the antistatic agent was changed as shown in Table 3.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention;
FIG. 2 is a sectional view of the sheet. In the figure, 1 is a stainless steel frame, 2 is a differential pressure molding sheet (lining material), 2a and 2c are antistatic resin layers,
3 is a cavity, 4' is a urethane foam, and 5 is an injection port.

Claims (1)

[Claims] 1. A composite heat insulating material having a structure in which a polyolefin resin or a styrene resin and a urethane foam are laminated with an adhesive containing the following components (A) and (B). Adhesive composition: (A) 20 to 100% by weight of a water-soluble polyimine compound selected from the group consisting of polyethyleneimine, poly(ethyleneimine-urea) and ethyleneimine adducts of polyamine polyamides (B) Nitrogen-containing cationic or Amphoteric polymer 80-0% by weight 2 A patent claim characterized in that component (B) is an amphoteric compound obtained by modifying the tertiary nitrogen atom of a polymer consisting of the following components (a) to (c) with an amphoteric agent. Composite insulation material according to item 1. (a) [Formula] 20-40% by weight (b) [Formula] 60-80% by weight (c) Other hydrophobic vinyl monomers 0-20% by weight [However, in each formula, R ¹ is H or _CH3 , ^R2
and R ³ are each an alkyl group having 1 to 2 carbon atoms, R ⁵ is an alkyl group having 1 to 18 carbon atoms, and A
is an alkylene group having 2 to 6 carbon atoms]