KR100345490B1 - Closed cell polyurethan form with enhanced insulating capability and method for a preparation of the same - Google Patents

Abstract

The present invention needs to include perfluoroalkane to increase the compatibility between these alternative blowing agents and polyols in closed cell rigid polyurethane foams using hydrocarbon as the blowing agent to increase the premix storage of the polyurethane foam stock solution and to increase the thermal conductivity. In order to increase the compatibility between perfluoroalkane and polyol, the present invention provides a closed cell polyurethane foam including an emulsifier and a method of manufacturing the same, and provides a closed cell rigid polyurethane foam, and also uses a heat insulating material including the same. It can reduce power consumption and improve performance.

Description

CLOSED CELL POLYURETHAN FORM WITH ENHANCED INSULATING CAPABILITY AND METHOD FOR A PREPARATION OF THE SAME}

The present invention relates to a polyurethane foam and a composition for producing closed cell rigid polyurethane foam with improved thermal insulation performance.

Polyurethane foam is mainly used as the core material of vacuum insulation material, and vacuum insulation material is generally used as silica filler type, closed cell rigid polyurethane foam type, open cell rigid polyurethane foam type and glass fiber filler type depending on the core material to be filled. The silica filled type is limited in its use because dust is generated and heavy in manufacturing, and the glass wool filled type has a problem of high manufacturing cost, whereas the rigid polyurethane foam filled type has a weight that is higher than that of the silica filled type. It is light and easy to mass produce, so it is widely used.

In addition, the vacuum insulation core using polyurethane foam has a continuous type and a batch type according to its manufacturing method, and a mold for compressing the foam by injecting the raw liquid into a laminate method and a mold in which the raw liquid is flowed between upper and lower conveyor belts to manufacture the core. It can be classified by compression method, the composition and properties of the stock solution composition used depends on the preparation method. According to the cell structure, there are open cell or continuous cell polyurethane foam, independent cell polyurethane foam, and semi-independent semi-continuous cell polyurethane foam.

Conventional closed cell rigid polyurethane foam preparation compositions consist of i) polyol compositions, ii) polyisocyanates, and iii) blowing agents such as HCFC-141b and water, silicone surfactants, and catalysts. However, recently, in order to solve the two problems of prohibiting the use of CFC or HCFC compounds that cause environmental problems in refrigerators and energy saving, a low boiling point hydrocarbon such as cyclopentane or pentane is used as a blowing agent to replace the freon blowing agent. Although closed-cell rigid polyurethane foams have been produced, the compatibility of polyols for producing polyurethane foams with these cyclopentane or pentane blowing agents is reduced, which reduces the shelf life of polyurethane foam premixes and is relatively low compared to CFC and HCFC foams. There is a problem of having a thermal conductivity.

In the manufacture of closed-cell rigid polyurethane foams, to solve the problem of high thermal conductivity caused by using hydrocarbons such as pentane and cyclopentane, which are environmentally friendly foaming agents, the cell size is reduced to improve the thermal conductivity. Nucleators, such as perfluroroalkane, may also be added, but such perfluoroalkanes have a high binding strength and are poorly emulsified with other materials, and have poor properties to maintain these conditions. There is a problem in that the compatibility is poor, so the storage stability and compatibility of the polyol premix can not be used.

Accordingly, there is an urgent need for closed cell rigid polyurethane foams using alternative blowing agents such as hydrocarbons having low thermal conductivity.

In order to solve the above problems, the present invention in the manufacture of closed-cell rigid polyurethane foam using a hydrocarbon as a blowing agent, a closure comprising perfluoroalkane (PFA) and emulsifiers, polyols, organic isocyanates, and catalysts It is an object of the present invention to provide a composition for producing cell rigid polyurethane foam and a polyurethane foam prepared therefrom.

Provided is a method for producing a closed cell rigid polyurethane foam having a small cell size and low thermal conductivity by adding perfluoroalkane and an emulsifier to the composition for preparing a rigid polyurethane foam.

1 is a cross-sectional photograph of a conventional rigid polyurethane foam.

Figure 2 is a cross-sectional photograph of a rigid polyurethane foam which is an example of the present invention.

Figure 3 shows an improvement in jeon according to the reduction of the K-factor value of the rigid polyurethane foam as an example of the present invention.

The present invention relates to a closed cell rigid polyurethane foam using a hydrocarbon having a low thermal conductivity and reducing the cell size, and to a closed cell containing perfluoroalkane (PFA) and an emulsifier, a polyol, an organic isocyanate, and a catalyst. It relates to a composition for producing a cell rigid polyurethane foam and a polyurethane foam prepared therefrom.

The present invention relates to a composition for producing closed-cell rigid polyurethane foam and a polyurethane foam prepared therefrom, the composition of which is as follows:

1) 100 parts by weight of polyol for producing rigid polyurethane foam,

2) 1-20 parts by weight of a hydrocarbon blowing agent, 0.1-4.9 parts by weight of perfluoroalkane, 0.1-10 parts by weight of an emulsifier for stabilizing polyol premixes, 1.4-2.0 parts by weight of water, a catalyst, and

3) Index 90-200 of organic polyisocyanates.

The present invention uses hydrocarbons as volatile alternative blowing agents, CFCs and HCFCs, with cyclopentane or pentane being preferred.

The emulsifier of the present invention may be an aromatic C _6-20 primary alcohol, an aliphatic C _5-20 primary alcohol, or a polyether polyol compound having a number average molecular weight of 100-5000 polymerized with an alkylene oxide on a primary alkylamine. It is used to ensure the storage stability and compatibility of the perfluoroalkane and polyol acid, and is preferably about 0.1-10 parts by weight based on 100 parts by weight of the polyol. The emulsifier is initially added perfluoroalkane and then mixed at a high speed by 3,000 rpm rotation with a homomixer or circulated by a high-pressure pump. The emulsification conditions, storage conditions and viscosity of the premix have a great effect on the storage stability. Crazy It is an important factor in preparing the mixing ratio or emulsion foam at the time of foaming.

The perfluoroalkane added to the nucleator to increase the compatibility of the polyol and the hydrocarbon blowing agent in the present invention is preferably C _4-6 alkanes containing one or more fluoro atoms, more preferably C ₆ F ₁₄ . 0.1-4.9 weight part is suitable for the usage-amount, and 2.0-3.0 are more preferable. The perfluoroalkane emulsified in the premix at the time of foaming increases the nucleation effect in the early stage of the reaction and suppresses cell growth by reducing the interfacial tension of the premix by the perfluoroalkane. In addition, the cell size can be reduced compared to the conventional closed cell polyurethane foam because the initial cell size is maintained by curing the initially generated microcell while preventing overlapping between cells. Accordingly, the conventional polyurethane foam having the composition shown in Table 1 has a cell size of 150-350 μm, whereas the cell size of the polyurethane foam of the present invention has 80-150 μm, so that the K-factor value (thermal conductivity) is It is reduced and the thermal insulation performance is improved. Therefore, the refrigerator using the polyurethane foam as a core has an advantage of improving power consumption and improving basic performance.

The catalyst used in the present invention is composed of a blowing catalyst (catalyst A), a gelling catalyst (gelling catalyst (catalyst B), and an isocyanate trimerization catalyst), and the relevance and reactivity of these catalysts are suited to the practical conditions. It is necessary to adjust the amount of catalyst to be suitable for the system, since only polyurepan foam having proper characteristics can be produced. Catalyst A is a strong foaming catalyst that affects the reactivity of the foam, typically TMHDA (N, N- tetramethylhexanediamine), and when a large amount of the catalyst A is injected into the mold and the rapid foaming This is because the foam is formed and the time control for the compression in the mold is disadvantageous, which adversely affects the physical properties of the entire core material. Catalyst B functions as a gelling catalyst, and it is preferable to use dipropylene glycol and triethylenediamine in a 2: 1 mixture. As for the usage-amount of these catalysts A and B, 1.3-1.7 are suitable for 100 weight part of total polyols. Examples of isocyanate trimerization catalysts include metal spirits of organic carboxylic acids, tertiary amine compounds and quaternary ammonium salts, and 0.3-0.5 is preferred for 100 parts by weight of polyol.

As the polyol usable in the present invention, all polyols for preparing rigid polyurethane foams may be used. Examples include compounds having ester groups, ethylene glycol, glycerin, trimethylpropane, sorbitol, sucrose, ethylene diamine (EDA), diethylenetriamine, Polyols obtained by polymerizing alkylene oxides such as ethylene oxide and propylene oxide butylene oxide, using organic oxides such as toluenediamine (TDA) and diphenylmethanediamine as initiators.

The organic isocyanate used in the present invention can use all of the conventional isocyanate for the production of polyurethane foam, the R / P ratio of the general polyurethane foam is preferably about 1.06- 1.1 and the amount of the isocyanate is 90-200 for the polyol It is preferable to use.

The present invention relates to a method for producing a closed cell rigid polyurethane foam, and specifically, an organic isocyanate is reacted with a premix added with a polyol, a catalyst, a silicone surfactant, an additive, water, and a blowing agent in the closed cell rigid polyurethane foam composition. To make it.

The present invention will be described in more detail with reference to the following Examples. However, the following examples are presented by way of example only and are not intended to limit the protection scope of the present invention thereto.

Example

Example 1: Polyurethane foam of the present invention and its physical properties

In the composition shown in Table 1, polyisol, a catalyst, a silicone surfactant, an additive, water, and a premixed additive are prepared by reacting an organic isocyanate in a high pressure foam injector. The polyurethane foam core material thus prepared was sufficiently dried in a high temperature dryer, and then put into a thin film-treated aluminum film having a thickness of 100 μm or less and sealed under vacuum to prepare a vacuum insulation material.

Configuration Kinds usage Polyol Sorbitol 20-40 TDA 40-50 Ester compounds 2-10 EDA 5-10 Emulsifier 0.1-10 catalyst Foaming catalyst / gelling catalyst 1.3-1.7 Trimerization catalyst 0.3-0.5 Nuclear agent Perfluoroalkanes 2.0-3.0 water 1.4-2.0 Cyclopentane 14-16 Isocyanate Methyl diisocyanate (MDI) 140-150 R / P Ratio 1.06-1.10

After preparing the polyurethane foam, the cell size was measured using scanning electromicrophotograhs (SEM), and other physical properties were measured by conventional physical property measurement methods in the present invention. Specifically, Just Pack is a measure of the amount of polyurethane foam accurately filled in a predetermined volume when the stock solution is injected into a predetermined mold by weight, the reactivity is the main reaction time of the polyurethane foam (bar, The time when the stick starts to come out of the fiber when it is punctured by a stopwatch. For the K-factor measurement, after inserting the polyurethane foam of the present embodiment to be measured between the upper plate (10 ° C.) and the lower plate (38 ° C.) maintaining a constant temperature having a width, length, and thickness of 200 mm x 200 mm x 25 mm. The amount of heat insulation for this material was measured by the lazer comp Auto λ meter HC-074 (trade name, manufactured by LASERCOMP INC.). The compressive strength was measured by Zwick's UTM meter after compressing the specimen in a size of 40 mm x 40 mm x 40 mm in width, length, and thickness to 10% on a test scale of 50 mm / min. The post-expansion rate was measured using a dimensional measurement device when the mold was demolded before the foam was completely cured in a certain mold. In addition, the dimensional change rate refers to the dimensional change according to the environmental conditions (eg, temperature and humidity) of the product, and the change rate was calculated by measuring the front and rear dimensions by using the thermostat and the measuring device. .

The physical properties of the polyurethane foam of the present invention are shown in Table 4 below. The K-factor reduction value is shown in FIG. 3.

Properties of Rigid Polyurethane Foam of the Present Invention Property value Just pack 560 g Reactivity (GT) 48 ± 5 seconds Free Foam Density 22 ± 0.5 kg / ㎡ K-factor 0.0157 kcal / mhr ℃ Core density 32.98 kg / ㎡ Compressive strength 1.78 / 2.35 kg / ㎠ Post expansion 3.12% Low temperature dimensional change rate 0.42% Fine dimensional change rate 0.47% High temperature and humidity change rate 2.39%

Comparative Example 1: Conventional Polyurethane Foam and Netting

The composition and physical properties of a conventional closed cell rigid polyurethane foam are as follows.

Ingredient content Polyol Sorbitol Base 40-50 TDA 30-40 glycerin 20-30 catalyst Foaming catalyst / gelling catalyst 0.3-0.6 Foaming catalyst 1.5-2.5 Trimerization catalyst 0.3-0.5 Surfactants silicon 1.5-2.5 water 2.0-2.5 Cyclopentane 14-16 MDI Polymer 140-150 R / P Ratio 1.24-1.30

Properties of Closed Cell Rigid Polyurethane Foam Property value Just pack 500 g Reactivity (GT) 48 ± 5 seconds Free Foam Density 22 ± 0.5 kg / ㎡ K-factor 0.0168 kcal / mhr ℃ Core density 30.51 kg / ㎡ Compressive strength 1.66 / 2.33 kg / ㎠ Post-expansion rate 2.36% Low temperature dimensional change rate 0.55% Fine dimensional change rate 0.59% High temperature and humidity change rate 2.16%

The present invention needs to include perfluoroalkane in order to increase the premix storage of the polyurethane foam stock solution and increase the thermal conductivity by increasing the compatibility between these alternative blowing agents and polyols in a closed cell rigid polyurethane foam using hydrocarbon as a blowing agent. However, in order to increase compatibility between perfluoroalkane and polyol, a closed cell polyurethane foam including an emulsifier is provided and a manufacturing method thereof, thereby providing a closed cell rigid polyurethane foam and using a heat insulating material including the same. It can reduce power consumption and improve performance.

Claims (5)

1) 100 parts by weight of polyol for producing rigid polyurethane foam, 2) 1-20 parts by weight of a hydrocarbon blowing agent, 0.1-4.9 parts by weight of perfluoroalkane, 0.1-10 parts by weight of an emulsifier for stabilizing polyol premixes, water, a catalyst, and 3) A composition for producing a closed cell rigid polyurethane foam comprising 90-200 parts by weight of an organic polyisocyanate. The composition of claim 1, wherein the hydrocarbon blowing agent is cyclopentane or pentane. According to claim 1, wherein the emulsifier is a polyether system having a number average molecular weight of 100-5000 polymerized alkylene oxide to aromatic C _6-20 primary alcohol, aliphatic C _5-20 primary alcohol, or primary alkylamine A composition for producing a closed cell rigid polyurethane foam, which is a polyol compound. The composition of claim 1, wherein the perfluoroalkane is a C _4-6 alkan containing at least one fluoro atom. A closed cell rigid polyurethane foam prepared from the composition according to any one of claims 1 to 4 and having a cell size of 80-150 μm.