Blowing agent composition, composition capable of reacting with isocyanate

Abstract

The present invention discloses a foaming agent composition and a composition capable of reacting with isocyanate. The foaming agent composition is characterized in that it comprises a physical foaming agent component and a chemical foaming agent component, wherein the chemical foaming agent component contains glycerol carbonate, and the physical foaming agent component contains a compound F with a boiling point greater than 35°C and inert to both isocyanate and polyol, and the molar ratio of the compound F to the glycerol carbonate is greater than 1. The composition capable of reacting with isocyanate comprises a polyol component and the aforementioned foaming agent composition, wherein the polyol component contains polyether polyol and / or polyester polyol, a foam stabilizer and a catalyst, and the water-free hydroxyl value of the polyol component is 300 to 500 mgKOH / g. The present invention uses an environmentally friendly new foaming agent system, which can effectively improve the thermal conductivity of rigid polyurethane foam, while also taking into account better comprehensive foam performance.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical synthesis, and in particular relates to a foaming agent composition and a composition capable of reacting with isocyanate. Background Art

[0002] Foaming agent is an important raw material required for the production of rigid polyurethane foam. The molecular weight, boiling point, specific heat capacity, gas-phase thermal conductivity, reaction activity and other characteristics of the foaming agent will affect the formation and distribution of polyurethane material pores. At the same time, the gas-phase thermal conductivity of the foaming agent component inside the pores is also one of the main influencing factors that determine the thermal insulation properties of rigid polyurethane foam.

[0003] Generally, foaming agents can be divided into physical foaming agents and chemical foaming agents, among which chemical foaming agents mainly react with isocyanates to indirectly generate gaseous substances to achieve foaming. Commonly used chemical foaming agents are mainly water, in addition to organic amine salt compounds containing carbon dioxide donor anions, glycerol carbonate, etc. Since the above chemical foaming agents all generate carbon dioxide as the final gas phase component, and the gas phase thermal conductivity of carbon dioxide is relatively high, the current chemical foaming agent formulation systems all have the disadvantage of high thermal conductivity.

[0004] For example, CN107089910A discloses organic amine carbonate salt compounds and their use as foaming agents, which discloses the use of at least one of carbamate, carbonate, formate, bicarbonate, organic (base) monocarbonate, and organic (base) polycarbamate as a carbon dioxide donor anion, and the organic amine salt formed with the organic amine compound can decompose and release carbon dioxide during contact with isocyanate, thereby playing the role of a chemical foaming agent, but the thermal conductivity of the obtained rigid polyurethane foam is >20mW / (m·K);

[0005] Another example is CN118344641A, which discloses a foaming agent composition for polyurethane and a method for preparing polyurethane foam using the same. It discloses a foaming agent composition containing glycerol carbonate and methyl formate, which can solve the problem of reduced initial foaming performance caused by the exothermic reaction of cyclic carbonate and isocyanate. However, the thermal conductivity of the obtained rigid polyurethane foam is still relatively high, ≥19 mW / (m·K).

[0006] As the demands for energy conservation and environmental protection become increasingly prominent, the market requires that the thermal conductivity of polyurethane materials be as low as possible. Physical foaming agents with low thermal conductivity are usually used to obtain better thermal insulation performance, but their global warming potential (GWP) is usually high. Although chemical foaming agents have the advantage of a GWP value of zero, their thermal insulation performance is relatively poor. Therefore, in order to further improve the beneficial role of polyurethane materials in the field of energy conservation and environmental protection, the development of low thermal conductivity foaming technology is still a hot spot and difficulty in research in this field. Summary of the invention

[0007] The purpose of the present invention is to further reduce the thermal conductivity of polyurethane materials of an environmentally friendly foaming agent system.

[0008] To achieve the above-mentioned object, the present invention first provides a blowing agent composition, comprising a physical blowing agent component and a chemical blowing agent component, wherein the chemical blowing agent component contains glycerol carbonate, and the physical blowing agent component contains a compound F having a boiling point greater than 35° C. and being inert to isocyanate and polyol reactions, wherein the molar ratio of the compound F to the glycerol carbonate is greater than 1.

[0009] The applicant has found through research that the use of glycerol carbonate and a compound F with a specific boiling point in a specific ratio can effectively slow down the destruction of the foam cells by the heat released by glycerol carbonate during the reaction. When the boiling point of compound F is less than 35°C, the improvement effect on the heat release problem is not obvious, which is detrimental to the formation and stability of the foam cells. In order to ensure that the physical foaming agent component absorbs the reaction heat in time and transforms from liquid phase to gas phase in time during the reaction, it is preferred that the boiling point of the compound F is greater than 35°C and less than 50°C, and the molar amount of the compound F is greater than the molar amount of the glycerol carbonate, that is, the molar ratio of the compound F to the glycerol carbonate is greater than 1, such as 1.5 to 40.0.

[0010] The compound F inert to both isocyanate and polyol described in the present invention is a substance that only acts as a physical blowing agent during the preparation of polyurethane and does not react with main raw materials such as polyol and isocyanate. The compound F can be selected from alkane compounds with a boiling point greater than 35°C and non-alkane compounds with a boiling point greater than 35°C. The non-alkane blowing agent can be selected from fluoroolefins and chloroolefins, such as cis-1-chloro-3,3,3-trifluoropropene, trans-1,2-dichloroethylene, etc.

[0011] In order to further take into account environmental protection and the fluidity of the polyurethane material system during the reaction, the compound F is preferably an alkane compound, such as cyclopentane and / or n-pentane.

[0012] Furthermore, in order to take into account the stability of low-density foam, the physical foaming agent component preferably also contains an alkane compound B with a boiling point of less than 0°C, such as at least one of n-butane, isobutane, and propane, and the amount of the compound B is less than 20%, such as 1 to 16%, based on the total mass of the physical foaming agent component.

[0013] As another solution that takes into account the fluidity of the material system, it is further preferred that the chemical foaming agent component also contains water, and the amount of water is ≥ 9%, such as 9-80%, based on the total mass of the chemical foaming agent component.

[0014] When polyurethane material is used to fill the filling cavity of products such as refrigerators and freezers, it will form a bond with the inner wall of the cavity. The quality of the adhesion directly affects the appearance and insulation performance of terminal products such as refrigerators. Therefore, in order to further take into account the adhesion and fluidity of the material, it is preferred that the amount of water is less than 40%, such as 9-40%, based on the total mass of the chemical foaming agent component. Furthermore, in the process of preparing rigid polyurethane foam, it is usually necessary to take into account good fluidity, thermal insulation, uniformity of density distribution and bonding strength. At the same time, in order to match the material system of rigid polyurethane foam, the components in the foaming agent composition of the present invention can be vaporized in time during the reaction process of generating polyurethane and finally generate a good pore structure. Preferably, the foaming agent composition is composed of the following materials in mass proportion: 3-45% of glycerol carbonate, 3-17% of water, 40-85% of alkane compounds with a boiling point greater than 35°C, and 0-17% of alkane compounds B with a boiling point less than 0°C, and further 3.5-44.0% of glycerol carbonate, 3.5-14.0% of water, 44.0-84.0% of alkane compounds with a boiling point greater than 35°C, and 0-13% of alkane compounds B with a boiling point less than 0°C.

[0015] Secondly, the present invention provides a composition capable of reacting with isocyanate, which comprises a polyol component and the foaming agent composition of the present invention, wherein the polyol component contains polyether polyol and / or polyester polyol, a foam stabilizer and a catalyst, and the average hydroxyl value of the polyol component without water is 300 to 500 mgKOH / g. In order to take into account better comprehensive foam performance, the average hydroxyl value of the polyol component without water is preferably 350 to 496 mgKOH / g.

[0016] The polyether polyol is usually prepared by ring-opening polymerization of an active hydrogen-containing compound (such as a polyol and / or a polyamine) with an oxidized olefin component as an initiator. The initiator can be selected from sucrose, sorbitol, mannitol, diethylene glycol, trimethylolpropane, glycerol, pentaerythritol, alcohol amines, aromatic amines, alicyclic amines, etc.

[0017] Polyester polyols are usually formed by condensation of organic dicarboxylic acids (anhydrides or esters) and small molecule polyols (including diols) or by polymerization of lactones and polyols. Among them, the dicarboxylic acids (anhydrides or esters) can be selected from phthalic anhydride, terephthalic acid, dimethyl terephthalate, adipic acid, etc., and the small molecule polyols can be selected from ethylene glycol, propylene glycol, butanediol, propylene glycol, trimethylolpropane, pentaerythritol, hexanediol, etc.

[0018] The catalyst is used to catalyze the reaction involving isocyanate groups to catalyze the formation of carbamate bonds, urea bonds or isocyanurate bonds. The conventional types in the art can be used, and can be selected from any one or more of pentamethyldiethylenetriamine, bis(dimethylaminoethyl)ether, tetramethylhexanediamine, dibutyltin dilaurate, N-ethylmorpholine, N,N-dimethylcyclohexylamine, triethylenediamine, 1,2-dimethylimidazole, dimethylbenzylamine, 1,3,5-tris(dimethylaminopropyl)hexahydrotriazine, 2,4,6-tris(dimethylaminomethyl)phenol, methyl quaternary ammonium salt, potassium octanoate, potassium 2-ethylhexanoate, potassium acetate, (2-hydroxypropyl)trimethylammonium formate, ethyl quaternary ammonium salt, and octyl quaternary ammonium salt. When two or more catalysts are selected, they can be mixed in any proportion.

[0019] Foam stabilizers are usually polyether-modified silicone surfactants for rigid foams that have emulsifying and nucleating effects. They have a high boiling point and are in liquid phase during the polyurethane reaction process. They contain polysiloxane segments and polyoxyalkylene segments, and are mainly Si-C type chain structures. For the foaming agent composition of the present invention, conventional or special types in the art can be used. Therefore, the present invention does not further limit the surface tension of the foam stabilizer, and conventional foam stabilizers with a surface tension of ≥25.0 mN / m can be used. In addition, in order to achieve a lower thermal conductivity, foam stabilizers with a surface tension of <25 mN / m can also be used, but a specific preparation method is required to match it. The present invention adopts conventional foam stabilizer types in the art and a preparation method of premixing conventional polyols and foaming agents to obtain rigid polyurethane foams with excellent performance.

[0020] Furthermore, in order to improve the adaptability between the foaming agent composition and the reaction material components and ensure that the obtained rigid polyurethane foam has a higher closed cell rate, the pH value of the 4% aqueous solution of the polyether-modified silicone surfactant is preferably 5-9.

[0021] In order to obtain a lower core density, the present invention preferably requires 18 to 30 parts of the blowing agent composition of the present invention for every 87 to 97 parts of the polyol composition, that is, the composition capable of reacting with isocyanate of the present invention is composed of 87 to 97 parts of the polyol component and 18 to 30 parts of the blowing agent composition, wherein the blowing agent composition is composed of the following substances in parts by weight: 0.5 to 10 parts of glycerol carbonate, 1.0 to 2.5 parts of water, 10 to 16 parts of alkane compounds with a boiling point greater than 35°C, and 0 to 3.0 parts of alkane compound B with a boiling point less than 0°C.

[0022] In general, the comprehensive advantages of this application are: the use of an environmentally friendly new foaming agent system can effectively improve the thermal conductivity of rigid polyurethane foam, while also taking into account better comprehensive foam performance. DETAILED DESCRIPTION

[0023] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0024] The sucrose polyether polyols used in the preparation of rigid polyurethane foam in the embodiment of the present invention are H4110M and H8169, the sorbitol polyether polyols are H6007 and H635SG, and the glycerol polyether polyols are H307 and H303, all of which are purchased from Hongbaoli Group; the aromatic amine polyether polyol is 736, 922, both purchased from BASF; phthalic anhydride polyester polyol is

[0025] PS-2352, purchased from Stepan;

[0026] The composite catalyst is pentamethyldiethylenetriamine, N,N-dimethylcyclohexylamine, (2-hydroxypropyl)trimethylammonium formate and 1,3,5-tris(dimethylaminopropyl)-hexahydrotriazine in a mass ratio of 0.3:1.5:0.3:0.5;

[0027] The foam stabilizers used are all conventional, and their surface tension is greater than 25.0 mN / m, such as B8460, pH value of 4% aqueous solution is 9.0; B8466, pH value of 4% aqueous solution is 5.5; B8469, pH value of 4% aqueous solution is 6.0; B8476, pH value of 4% aqueous solution is 5.0; B8484, 4% aqueous solution, pH value is 8.0, both purchased from Evonik.

[0028] Organic isocyanate M20s, purchased from BASF.

[0029] The preparation of the rigid polyurethane foam of the present invention is that the polyol component and the foaming agent composition are firstly mixed uniformly to obtain a composition capable of reacting with isocyanate, and then the composition and the organic isocyanate are mixed by high-speed stirring and injected into a mold, and then cured and formed, wherein the material temperature is 20±5°C, the mold temperature is 38-42°C, and the mold cavity size is 2000mm×200mm×50mm.

[0030] The apparent core density, dimensional stability, thermal conductivity, bonding strength and compression strength are all carried out in accordance with the method in GB / T 26689-2024 Rigid polyurethane foam for refrigerators and freezers. The bonding strength test uses PCM steel plate for refrigerator shell as the substrate; the density distribution uniformity is expressed by the core density range, which is the difference between the maximum core density and the minimum core density measured at different sampling points on the same sample; the expansion rate after 2min demoulding is the thickness change rate of the foam measured from the start of injection to 2min after demoulding (the difference between the maximum foam thickness after demoulding and the mold thickness as a percentage of the mold thickness). The shorter the demoulding time and the smaller the thickness change rate, the better the curing performance. .

[0031] The foaming agent composition used in the present invention is as follows:

[0032] 1# foaming agent composition: cyclopentane, glycerol carbonate, n-butane and water in a mass ratio of 16:9.8:1.7:1;

[0033] 2# foaming agent composition: cyclopentane, glycerol carbonate and water in a mass ratio of 16:6.6:1.5;

[0034] 3# foaming agent composition: cyclopentane, glycerol carbonate, propane and water in a mass ratio of 16:3.3:0.2:2.0;

[0035] 4# foaming agent composition: cyclopentane, n-pentane, glycerol carbonate and water in a mass ratio of 10:5:0.7:2.4;

[0036] 5# foaming agent composition: n-pentane, glycerol carbonate and water in a mass ratio of 10:9.8:2.5;

[0037] Composition of 6# foaming agent: cyclopentane, glycerol carbonate, isobutane and water in a mass ratio of 13:8.4:0.8:2.4;

[0038] 7# foaming agent composition: cyclopentane, glycerol carbonate and water in a mass ratio of 13:5.1:2.3;

[0039] 8# foaming agent composition: n-pentane, glycerol carbonate, n-butane, isobutane and water in a mass ratio of 16:1.7:2:1:2.4;

[0040] D1# foaming agent composition: cyclopentane and water in a mass ratio of 16:2.5;

[0041] D2# foaming agent composition: glycerol carbonate and water in a mass ratio of 25:2.5;

[0042] D3# foaming agent composition: cyclopentane, n-butane and water in a mass ratio of 13:2.5:2.5;

[0043] D4# foaming agent composition: glycerol carbonate, water and methyl formate in a mass ratio of 10:2.5:10;

[0044] D5# foaming agent composition: n-pentane, glycerol carbonate and water in a mass ratio of 15:1.0:2.3;

[0045] D6# foaming agent composition: cyclopentane, glycerol carbonate and water in a mass ratio of 7:15:2.5.

[0046] The material composition of the polyol component used in the present invention is shown in Table 1.

[0047] Table 1 Material composition of polyol components P-1# to P-8#

[0048]

[0049]

[0050] The rigid polyurethane foam was prepared using the formulations in Tables 2-3, and the properties of the prepared materials were characterized. The results are shown in Tables 4-5.

[0051] Table 2 Raw material formula required for preparing the rigid polyurethane foam of the embodiment

[0052]

[0053] Table 3 Raw material formula required for preparing comparative rigid polyurethane foam

[0054]

[0055] Table 4 Performance characterization results of rigid polyurethane foam in Example

[0056]

[0057] Table 5 Performance characterization results of comparative example rigid polyurethane foam

[0058]

[0059] As can be seen from the data in Table 4 and Table 5, the use of the foaming agent composition of the present invention can effectively reduce the thermal conductivity of the rigid polyurethane foam, and has good demoulding properties, density distribution uniformity and other comprehensive properties, and the chemical foaming agent and physical foaming agent used in the present invention are both green and environmentally friendly. Comparative Examples 1 and 2 use cyclopentane and glycerol carbonate separately, respectively, and the thermal conductivity of the obtained rigid polyurethane foam is relatively high. Comparative Example 3 uses butane composite foaming technology, and the thermal conductivity is higher than that of the cyclopentane system. Comparative Example 4 uses glycerol carbonate in combination with other types of physical foaming agents, and the cell structure is poor, and the thermal conductivity and dimensional stability are not as good as the present invention. The molar ratio of glycerol carbonate to compound F in Comparative Examples 5 and 6 exceeds the range, and the performance of the obtained rigid polyurethane foam is not ideal.

Claims

1. A foaming agent composition, characterized in that The invention comprises a physical foaming agent component and a chemical foaming agent component. The chemical foaming agent component contains glycerol carbonate. The physical foaming agent component contains a compound F with a boiling point greater than 35° C. and inert to both isocyanate and polyol. The molar ratio of the compound F to the glycerol carbonate is greater than 1.

2. The foaming agent composition according to claim 1, characterized in that The compound F is an alkane compound.

3. The foaming agent composition according to claim 1, characterized in that The physical foaming agent component also contains an alkane compound B with a boiling point of less than 0°C.

4. The blowing agent composition according to claim 3, characterized in that Based on the total mass of the physical blowing agent component, the amount of the compound B is less than 20%.

5. The blowing agent composition according to claim 1, characterized in that The chemical blowing agent component also contains water.

6. The blowing agent composition according to claim 5, characterized in that Based on the total weight of the chemical foaming agent component, the amount of water is less than 40%.

7. The blowing agent composition according to any one of claims 1 to 6, characterized in that The material is composed of the following materials in proportion by weight: 3-45% of glycerol carbonate, 3-17% of water, 40-85% of alkane compounds with a boiling point greater than 35° C., and 0-17% of alkane compound B with a boiling point less than 0° C.

8. A composition capable of reacting with isocyanate, characterized in that The invention comprises a polyol component and the foaming agent composition according to any one of claims 1 to 7, wherein the polyol component contains polyether polyol and / or polyester polyol, a foam stabilizer and a catalyst, and the water-free hydroxyl value of the polyol component is 300 to 500 mgKOH / g.

9. The composition capable of reacting with isocyanate according to claim 8, characterized in that The foam stabilizer is a polyether-modified organic silicon surfactant, and the pH value of a 4% aqueous solution thereof is 5-9.

10. The composition capable of reacting with isocyanate according to claim 8 or 9, characterized in that The foaming agent composition is composed of 87 to 97 parts of a polyol component and 18 to 30 parts of the foaming agent composition, wherein the foaming agent composition is composed of the following substances in parts by weight: 0.5 to 10 parts of glycerol carbonate, 1.0 to 2.5 parts of water, 10 to 16 parts of an alkane compound with a boiling point greater than 35°C, and 0 to 3.0 parts of an alkane compound B with a boiling point less than 0°C.

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