CN117940474A

CN117940474A - Polyurethane foam material and preparation method thereof, refrigerator and freezer

Info

Publication number: CN117940474A
Application number: CN202380013524.1A
Authority: CN
Inventors: 曹立军; 胡锋; 刘莉
Original assignee: Hisense Ronshen Guangdong Refrigerator Co Ltd
Current assignee: Hisense Ronshen Guangdong Refrigerator Co Ltd
Priority date: 2022-05-20
Filing date: 2023-04-12
Publication date: 2024-04-26
Also published as: WO2023221693A1; WO2023221694A1; WO2023221694A9; WO2023221693A9

Abstract

Discloses a polyurethane foam material and a preparation method thereof, a refrigerator and a freezer, and belongs to the technical field of high polymer materials. The polyurethane foam material disclosed by the disclosure comprises organic polyisocyanate and a white material composition, wherein the white material composition comprises the following components in parts by weight: 100 parts of polyol composition, 1.8-2.5 parts of water, 1.6-2.5 parts of foam stabilizer, 2-3 parts of catalyst and 26-38 parts of composite foaming agent; the composite foaming agent consists of a high-boiling point fluoroolefin foaming agent with the boiling point more than or equal to 5 ℃ and a low-boiling point fluoroolefin foaming agent with the boiling point less than or equal to-15 ℃. The polyurethane foam material prepared by adopting the fluoroolefin foaming system with high and low boiling points has low density, tiny and uniform cells, the heat conductivity coefficient of the polyurethane foam material is less than or equal to 16.5Mw/m.K, and the polyurethane foam material has excellent heat insulation performance; and the polyurethane foam material has strong shrink deformation resistance, high dimensional stability under low temperature condition and extremely low deformation degree.

Description

Polyurethane foam material and preparation method thereof, refrigerator and freezer

Cross Reference to Related Applications

The present disclosure claims priority to the filing of chinese patent office, chinese patent application number 202211499386.6, at 28, 2022, and priority to the filing of chinese patent office, chinese patent application number 202210549493.9, at 20, 2022, 5, the entire contents of which are incorporated herein by reference.

Technical Field

The disclosure relates to the technical field of high polymer materials, in particular to a polyurethane foam material and a preparation method thereof, a refrigerator and a freezer.

Background

The refrigerator or the ice chest is required to improve the volume ratio and is achieved by thinning the heat insulation layer of the refrigerator, and the hard polyurethane foam is used as a heat insulation material of the refrigerator and the ice chest, is one of key raw materials which directly influence the important use performance index of the refrigerator and the ice chest, and plays a role in the production efficiency and the electric energy consumption of a single refrigerator. The insulation layer of the refrigerator is too thin, and the insulation performance of the refrigerator is degraded.

Disclosure of Invention

In one aspect, a polyurethane foam is provided that includes an organic polyisocyanate and a white stock composition. The white material composition comprises, by weight, 100 parts of a polyol composition, 1.8-2.5 parts of water, 1.6-2.5 parts of a foam stabilizer, 2-3 parts of a catalyst and 26-38 parts of a composite foaming agent. The composite foaming agent consists of a high-boiling point fluoroolefin foaming agent with a boiling point of more than or equal to 5 ℃ and a low-boiling point fluoroolefin foaming agent with a boiling point of less than or equal to-15 ℃, wherein the high-boiling point fluoroolefin foaming agent is 25-35 parts, and the low-boiling point fluoroolefin foaming agent is 1-3 parts.

The polyurethane foam materials in some embodiments of the present disclosure have high thermal insulation properties and good resistance to shrinkage deformation. In the polyurethane foam material, a foaming system adopts a composite foaming agent composed of a high-boiling point fluoroolefin foaming agent with a boiling point of more than or equal to 5 ℃ and a low-boiling point fluoroolefin foaming agent with a boiling point of less than or equal to-15 ℃, the fluidity of foam raw material liquid is good, foam filling is uniform, the density of the prepared polyurethane foam material is low, fine and uniform foam cells are provided, the heat conductivity coefficient of the polyurethane foam material is less than or equal to 16.5Mw/m.K, and the polyurethane foam material has excellent heat preservation performance; and the polyurethane foam material has strong shrink deformation resistance, high dimensional stability under low temperature condition and extremely low deformation degree.

In another aspect, there is provided a method for preparing a polyurethane foam, comprising: mixing the polyol composition, water, foam stabilizer and catalyst at 20-30 ℃ to obtain a first mixture; mixing the first mixture and the high-boiling point fluoroolefin foaming agent through static premixing equipment at 15-20 ℃ and under the pressure of 1.0-2.5 MPa to obtain a second mixture; mixing the second mixture and the low-boiling point fluoroolefin foaming agent through static premixing equipment at 15-20 ℃ and under the pressure of 2.5-4.0 MPa to obtain a third mixture, namely a white material composition; and mixing and foaming the white material composition and the organic polyisocyanate in proportion through a high-pressure foaming gun head, wherein the gun head pressure is 110-160 bar, and the polyurethane foam material is prepared.

In still another aspect, a refrigerator is provided, including a casing, an inner container, and a heat insulation layer disposed between the casing and the inner container, where the heat insulation layer includes the polyurethane foam material according to any one of the embodiments.

In still another aspect, an ice chest is provided, including a housing, an inner container, and a thermal insulation layer disposed between the housing and the inner container, where the thermal insulation layer includes the polyurethane foam material according to any of the foregoing embodiments.

Drawings

FIG. 1 is an electron micrograph of a rigid polyurethane foam provided in accordance with some embodiments of the present disclosure;

fig. 2 is an electron micrograph of a conventional rigid polyurethane foam provided by some comparative examples of the present disclosure.

Detailed Description

The following description of the embodiments of the present disclosure will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present disclosure. All other embodiments obtained by one of ordinary skill in the art based on the embodiments provided by the present disclosure are within the scope of the present disclosure.

Throughout the specification and claims, unless the context requires otherwise, the word "comprise" and its other forms such as the third person referring to the singular form "comprise" and the present word "comprising" are to be construed as open, inclusive meaning, i.e. as "comprising, but not limited to. In the description of the specification, the terms "one embodiment", "some embodiments (some embodiments)", "exemplary embodiment (exemplary embodiments)", "example (example)", "specific example (some examples)", etc. are intended to indicate that a particular feature, structure, material, or characteristic associated with the embodiment or example is included in at least one embodiment or example of the present disclosure. The schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

As used herein, "about," "approximately" or "approximately" includes the stated values as well as average values within an acceptable deviation range of the particular values as determined by one of ordinary skill in the art in view of the measurement in question and the errors associated with the measurement of the particular quantity (i.e., limitations of the measurement system).

Currently, desirable environment-friendly blowing agents are alkanes (e.g., pentane, butane, etc.), and HFOs-type fluoroolefins (e.g., 1-chloro-3, 3-trifluoropropene, cis-1, 4-hexafluoro-2-butene). For HFOs olefin foaming agents, 1-chloro-3, 3-trifluoropropene (HFO-1233 zd) and cis-1, 4-hexafluoro-2-butene (HFO-1336 mzz) are mature in the prior art, but the products are expensive due to single goods sources and monopoly, the products are limited in productivity, and the refrigerator and freezer products belong to labor-intensive industries, so that the goods sources and the high cost of the novel foaming agents form important barriers for popularization and application in the field of household electrical insulation; while alkanes (e.g., hydrofluoroalkanes low boiling point blowing agents) have limited practical use due to their high gas thermal conductivity.

Therefore, the development of the environment-friendly rigid polyurethane foam with controllable cost, low heat conductivity coefficient and low foam density is an important research and development direction in the polyurethane heat preservation field of the current household appliances.

In some examples and comparative examples of the present disclosure, polyether polyol a has an average functionality of 6.0 and a hydroxyl number of 400 to 480mgKOH/g starting with sucrose and glycerol; the polyether polyol B takes o-toluenediamine as an initiator, the average functionality is 3.9, and the hydroxyl value is 330-420 mgKOH/g; the polyether polyol C takes sorbitol as an initiator, has an average functionality of 4.4 and a hydroxyl value of 400-450 mgKOH/g; the polyester polyol is prepared by condensing dicarboxylic acid and glycol, and has an average functionality of 2.8 and a hydroxyl value of 250-350 mgKOH/g.

The foam stabilizer, catalyst, organic polyisocyanate were used in the same manner in each of the parallel experiments.

Unless specifically stated otherwise, reagents, methods and apparatus employed in the present disclosure are conventional in the art. Reagents and materials used in the present disclosure are commercially available unless otherwise indicated.

In some embodiments, a polyurethane foam is provided comprising the components in parts by weight as shown in tables 1 and 2, respectively, and the method of preparation comprises steps S1 through S4.

In step S1, the polyol composition, water, foam stabilizer, catalyst were mixed at 20 to 30℃according to the formulation of Table 1 to obtain a first mixture.

In step S2, the first mixture and the high boiling point fluoroolefin foaming agent are mixed in proportion by static premixing equipment at 15-20 ℃ and under the pressure of 1.0-2.5 MPa, so as to obtain a second mixture.

In step S3, the second mixture and the low boiling point fluoroolefin foaming agent are mixed in proportion by static premixing equipment at 15-20 ℃ and under the pressure of 2.5-4.0 MPa, so as to obtain a third mixture, namely a white material composition.

And in the step S4, the white material composition and the organic polyisocyanate are mixed and foamed through a high-pressure foaming gun head in proportion, and the pressure of the high-pressure foaming gun head is 110-160 bar, so that the polyurethane foam material is prepared.

TABLE 1 component content (parts by weight) of polyurethane foam materials of examples 1 to 8

TABLE 2 component contents (parts by weight) of polyurethane foams of examples 9 to 16

Comparative examples 1 to 7

Comparative examples 1 to 7 each provide a polyurethane foam comprising components in parts by weight as shown in table 3, and the preparation method comprises steps S11 to S14.

In step S11, the polyol composition, water, foam stabilizer, and catalyst were mixed at 20 to 30℃according to the formulation of Table 3 to obtain a first mixture.

In step S12, the first mixture and the high boiling point fluoroolefin foaming agent are mixed in proportion by static premixing equipment at 15-20 ℃ and under the pressure of 1.0-2.5 MPa, so as to obtain a second mixture.

In step S13, the second mixture and the low boiling point fluoroolefin foaming agent are mixed in proportion by static premixing equipment at 15-20 ℃ and under the pressure of 2.5-4.0 MPa, so as to obtain a third mixture, namely a white material composition.

In step S14, the white material composition and the organic polyisocyanate are mixed and foamed through a high-pressure foaming gun head in proportion, and the pressure of the high-pressure foaming gun head is 110-160 bar, so that the polyurethane foam material is prepared.

TABLE 3 comparative examples 1 to 7 component contents (parts by weight) of polyurethane foams

[ Performance test ]

The polyurethane foam materials obtained in the above examples and comparative examples were tested, and specific test items, test methods and results are as follows:

molding core density: according to the density test of GB/T6343-2009 polyurethane foam, test conditions: the foam volume was measured by drainage method, foam density = foam weight/foam volume, sample size (50±1) mm× (50±1) mm, and at least 2 samples were taken for each location of 1 refrigerator or freezer product.

The density profile is the difference between the maximum and minimum molding core densities.

Pore diameter of cells: measurement was performed using a scanning electron microscope (Scanning Electron Microscope, SEM).

Thermal conductivity (10 ℃ C.): according to the heat flow meter method for measuring the steady-state thermal resistance and related characteristics of the GB/T10295-2008 heat insulation material.

Minimum compressive strength (vertical direction): the compressibility of the rigid foam was measured according to GB/T8813-2008.

Dimensional stability: according to the linear dimensions of GB/T8811-2008 foamed plastics and rubber, the test conditions are-20 ℃, 48h and-60 ℃ and 48h respectively.

The test results of the examples are shown in Table 4, and the test results of the comparative examples are shown in Table 5.

Table 4 test results of examples

Table 5 test results of comparative examples

The amount of the low boiling point fluoroolefin blowing agent in comparative example 3 was too large to be uniformly mixed with other components under conventional processing conditions.

According to the test results of tables 4 and 5, the polyurethane foam materials prepared in each example of the present disclosure have suitable cell pore diameters, low density, low thermal conductivity, good heat insulation performance, excellent shrinkage deformation resistance, and high dimensional stability at-20 ℃ and-40 ℃.

From examples 1 to 8, it can be seen that when the high boiling point fluoroolefin blowing agent is Z-HFO-1336mzz and the low boiling point fluoroolefin blowing agent is HFO-1243zf, the polyurethane foam material has both superior heat insulation performance and higher shrinkage deformation resistance.

From the test results of examples 1 and 9 to 12, it can be seen that the polyurethane foam material has better overall properties when the weight ratio of the high boiling point fluoroolefin foaming agent to the low boiling point fluoroolefin foaming agent is (12 to 15) to 1.

The comparative example 1 does not contain a low boiling point fluoroolefin blowing agent, and the weight ratio of the two blowing agents in the comparative example 2 is beyond the range defined by the present disclosure, so that it is difficult to produce a polyurethane foam material having both heat-insulating property and shrinkage deformation resistance. The amount of the low boiling fluoroolefin blowing agent in comparative example 3 is excessive and it is difficult to uniformly mix with other components under conventional processing conditions.

In comparative examples 4 to 7, the polyurethane foam material prepared by using the non-fluorinated olefin foaming agent has poor uniformity of cells, high thermal conductivity and poor dimensional stability at low temperature.

Application examples 1 to 4

The polyurethane foam material of the example 1 is used as a material of a heat insulation layer to prepare a 400L refrigeration and freezing thin-wall refrigerator, and the thickness of a foam layer in a foaming cavity of the refrigerator is 20-65 mm. Application example 1 differs from application example 3 in that the refrigerator of application example 3 does not use VIP (Vacuum Insulation Panel) boards.

The polyurethane foam material of the comparative example 7 is used as the material of the heat insulation layer in the application example 2 and the application example 4 to prepare a 400L refrigeration and freezing thin-wall refrigerator, and the thickness of a foam layer in a foaming cavity of the refrigerator is 20-65 mm. Application example 2 differs from application example 4 in that the refrigerator of application example 4 does not use a VIP panel.

The refrigerator is subjected to power consumption test, the test standard is the power consumption limit value and the energy efficiency grade of GB/T8059-2016 household and similar-purpose refrigerating appliances and GB 12021.2-2015 household refrigerators, and the test results are shown in Table 6.

Table 6 test results for application examples

As can be seen from the test results of table 6, the polyurethane foam of the present disclosure has excellent heat insulation properties, and the use of VIP panels can be reduced or eliminated by using the polyurethane foam of some embodiments of the present disclosure as a heat insulating layer of a refrigerator with thin walls.

Meanwhile, with the improvement of the living standard of people and the development of the refrigerator technology, the capacity of the refrigerator is larger and larger, the living space area of people is limited due to the high price in the city, and products with small volume and large capacity become the demands of more and more users, and the demands are realized by improving the capacity rate. The refrigerator or the ice chest is required to improve the volume ratio and is achieved by thinning the heat insulation layer of the refrigerator, and the hard polyurethane foam is used as a heat insulation material of the refrigerator and the ice chest, is one of key raw materials which directly influence the important use performance index of the refrigerator and the ice chest, and plays a role in the production efficiency and the electric energy consumption of a single refrigerator. The insulation layer of the refrigerator is too thin, the insulation performance of the refrigerator is reduced, and most of the refrigerators are realized by vacuum insulation panels (VIP panels) in order to achieve the same insulation performance after the refrigerator is thinned, and the cost of VIP is high, so that the price of an ultrathin refrigerator-freezer containing the VIP panels is usually much higher than that of a common refrigerator.

At present, the thickness of an ultrathin refrigerator and freezer insulating layer is about 20-60 mm, parts such as wires, tube bundles and the like in a refrigerator and freezer foaming cavity are distributed in a narrow space, and in the polyurethane foaming filling process, the flow channel of foaming raw materials is narrow and the flow channel resistance is increased, so that the polyurethane raw materials cannot flow sufficiently in the cavity, the polyurethane foam is not distributed uniformly enough, the phenomenon of poor filling is increased, the appearance quality of a refrigerator is affected increasingly, and more importantly, the poor insulating performance of the refrigerator or freezer can be caused.

Aiming at the problem of uneven polyurethane foam distribution, chinese patent application CN 115073694A discloses a hard polyurethane foam with low density and ultralow heat conductivity coefficient, wherein a foaming system used by the hard polyurethane foam is an LBA foaming agent, a butane foaming agent and a methyl formate modifier, and the saturated vapor pressure is utilized to be larger by adding the butane foaming agent, so that the foam density is reduced; by adding methyl formate, foam density uniformity and flowability are improved. However, the storage stability of the foam material formed by the methyl formate foaming agent is poor, and butane has a high gas heat conductivity coefficient, so that the influence of the fluoroolefin on the heat conductivity coefficient reduction can be weakened by using the butane foaming agent, and the heat insulation performance of the refrigerator is not good enough.

In addition, because the heat insulation layer is thinner, the shrinkage deformation resistance of the polyurethane foam is particularly important, and the polyurethane foam heat insulation material prepared by the conventional foam formula is easy to shrink locally, so that the appearance quality of the product is affected.

Therefore, there is a need to provide a polyurethane foam material having high heat insulating properties and good resistance to shrinkage deformation.

Some embodiments of the present disclosure also provide a rigid polyurethane foam comprising, in parts by weight: 100 parts of combined polyether, 16-23 parts of foaming agent, 1-3 parts of foaming auxiliary agent and 144-160 parts of organic polyisocyanate; wherein the foaming auxiliary agent is trifluoropropene.

The embodiment provides a rigid polyurethane foam, which is characterized by low cost, low foam density, ideal heat conductivity coefficient and the like on the basis of the prior cyclopentane foaming system (namely a cyclopentane system and a mixed foaming system taking cyclopentane as a main body), and then a proper amount of trifluoropropene is introduced as a foaming auxiliary agent to form the cyclopentane (or the mixed foaming system taking cyclopentane as the main body) +the trifluoropropene mixed foaming system.

The lower the thermal conductivity of the foam, the better the heat insulating property and the lower the energy consumption of the obtained product. The polyurethane foam has relatively fixed solid heat conductivity and foam matrix, so the heat insulation performance is mainly affected by two aspects: (1) The lower the gas phase heat conductivity coefficient of the foaming agent, the better the heat preservation performance of the foaming agent; (2) Cell pore size, the finer the cells, the better the thermal conductivity of the foam.

Based on the above, fluoroolefins have a low gas thermal conductivity and contain a plurality of fluorine atoms, and can increase the nucleation rate of polyurethane foam in the foaming process, and thus, the foam has excellent heat insulation properties. In addition, nucleation additives such as 3M company perfluoroolefins (e.g., 5357, fa-188, 5056, etc.) can be added, but these have significant drawbacks-toxicity or high global warming coefficients (Global Warming Potential, GWP), and are costly.

Further, the packing density of the foam is directly related to the cost of production, the lower the density of the foam, the less raw materials are used to produce the foam, and the lower the cost. Common fluoroolefins (e.g., 1-chloro-3, 3-trifluoropropene, cis-1, 4-hexafluoro-2-butene) foam, while achieving good insulating properties, have densities in excess of 30.5kg/m3 and still are costly.

The addition of the low-boiling point foaming agent to the foam can reduce the foam density (as low as 27.5-29.0 kg/m 3) under the premise of ensuring the foam strength. Typically, two types of low boiling point blowing agents are used to add to the foam, one type being alkanes such as n-butane (boiling point-0.5 ℃), isobutane (boiling point-11.7 ℃); another class is hydrofluorocarbon blowing agents such as HFC-134a (boiling point-26.2 ℃ C.), HFC-152a (boiling point-25.7 ℃ C.). However, the gas heat conductivity coefficient of the former is high, and the heat insulation performance of the foam is not good after the addition; the latter has been increasingly limited in application due to their relatively high GWP and the restricted nature of HFCs (fluorochlorohydrocarbons, hydrofluorocarbons) by environmental regulations in various countries. Based on the above, the present disclosure compares the performance of 5 low boiling point foaming aids including trifluoropropene and performs related experiments, and finally selects trifluoropropene as the foaming aid to be added into the current foaming system based on cyclopentane.

Further, the present disclosure selects trifluoropropene as the blowing aid for several main reasons:

1. the environment-friendly performance is excellent, the ozone depletion potential value (ODP, ozone Depletion Potential) is 0, and the GWP value is 4.

2. The characteristics of low boiling point and high vapor pressure are that the gas is wrapped in the cells in the foaming process at normal temperature and normal pressure, so that the shrinkage deformation resistance of the cells can be greatly improved, and the foam density is reduced.

3. The fluidity of the foam material can be improved in the foaming process, the density distribution of the foam can be improved, and the quality of the product can be improved.

4. The polyfluoro atomic structure is used as a low boiling point substance and has nucleating property, so that the prepared foam is finer and more uniform, and the heat conductivity of the foam can be improved.

The organic polyisocyanate may be specifically selected from one or a mixture of several of PM2010 of plummet Wanhua, PM200, M20s of 44V20L, BASF of Covestro, supra ec 5005 of Huntsman, PAPI27 of DOW, and PM2010 is preferable.

In some embodiments, the combined polyether includes at least a polyol composition, a foam stabilizer, a catalyst, and water.

In some embodiments, the polyol composition is a polyether monomer selected from at least one of an amine ether, a glycerol polyether, a sucrose polyether, a mannitol polyether, a sorbitol polyether, a glycerol sucrose polyether, a dimethylaniline polyether, or a polyester polyether; the foam stabilizer is an organosilicon compound; the catalyst is a composite catalyst of tertiary amines and organic tin.

In the above embodiment, the foam stabilizer is an organosilicon compound or an organosilicon compound, and its main structure is: the polysiloxane-alkylene oxide block copolymer may be specifically selected from B8460, B8461, B8462, B8465, B8471, B8474, B8476, B8481, etc. of Windfold; AK8805, AK8815, AK8812, AK8809, etc. of the mei company; one or a mixture of several of L6900, L6863, etc. of Michaelis corporation; the catalyst is a composite catalyst of tertiary amines and organic tin, and specifically any one or a combination of more than one of TMR-2, PC-5 (or A-1) and PC-8 can be selected.

In some embodiments, the blowing agent comprises 11 to 17 parts by weight of pentane, preferably 13 to 16 parts by weight, the pentane being cyclopentane or cyclopentane and isopentane in a mass ratio (7 to 9): (3-1).

In the above embodiment, the parts by weight of pentane may specifically be 11, 12, 13, 14, 15, 16, 17, or any value within the above-defined range may be selected according to actual needs, which falls within the scope of the present disclosure.

In some embodiments, the blowing agent further comprises at least one of 1-chloro-3, 3-trifluoropropene (HFO-1233 zd) or cis-1, 4-hexafluoro-2-butene (HFO-1336 mzz) in a weight fraction of 0 to 10, preferably 0 to 8.

In the above embodiments, the weight parts of 1-chloro-3, 3-trifluoropropene (HFO-1233 zd) or cis-1, 4-hexafluoro-2-butene (HFO-1336 mzz) may specifically be selected from 0,1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and any value within the above-defined range is selected according to actual needs to fall within the protection scope of the present disclosure.

The present disclosure also provides a method of preparing a rigid polyurethane foam, including steps S21 to S23.

In the step S21, the polyol composition, the foam stabilizer, the catalyst and the water are physically mixed according to the mass portion ratio at the temperature of 25+/-5 ℃ and stirred for 0.5-1.5 h to obtain a first mixture;

In step S22, uniformly mixing the foaming agent, the foaming auxiliary agent and the first mixture through a static mixer to obtain a second mixture;

In step S23, the second mixture and the organic polyisocyanate are mixed and foamed in proportion through a high-pressure gun head at the temperature of 20+/-3 ℃ and the gun head pressure is controlled to be 110-150 bar, so that the rigid polyurethane foam is prepared.

In order to more clearly describe the rigid polyurethane foam, the preparation method and the thermal insulation material, refrigerator or freezer containing the polyurethane foam provided by some embodiments of the present disclosure in detail, the following description will be made with reference to specific embodiments.

[ Test for screening Low boiling substance of foaming aid ]

In order to obtain the low-boiling point foaming auxiliary agent most suitable for the hard polyurethane foaming agent, five substances including trifluoropropene are comprehensively compared, and finally trifluoropropene is selected as the most suitable foaming auxiliary agent to be used, wherein the specific screening process is as follows:

TABLE 7 comparison of Low boiling Material Properties

As can be seen from the table, although HFC-134a and HFC-152a have lower boiling points and higher vapor pressures, the global warming coefficient is higher, and the HFC-134a and HFC-152a belong to HFCs substances and are limited by stricter environmental regulations at home and abroad; butane has good environmental protection performance, but the gas heat conductivity coefficient is relatively high, and the heat preservation performance of the prepared polyurethane foam cannot achieve a better effect; the trifluoropropene has low boiling point, high steam pressure, good environmental protection, low gas heat conductivity coefficient, and the structure containing multiple fluorine atoms has nucleating property, so that the heat preservation effect of foam can be further improved, and the trifluoropropene is an ideal low-boiling point foaming auxiliary agent.

Comparative example 8

The comparative example provides a rigid polyurethane foam and a method for preparing the same, specifically:

the rigid polyurethane foam comprises the following components in parts by weight:

100 parts of polyol composition, 2.1 parts of foam catalyst, 2.2 parts of foam stabilizer, 1.9 parts of water, 16 parts of foaming agent-pentane and 147 parts of organic polyisocyanate.

The preparation method of the rigid polyurethane foam comprises the following steps:

(1) According to the mass portion ratio, the polyol composition, the foam stabilizer, the foam catalyst and the water are physically mixed at the temperature of 25+/-5 ℃ and stirred for 0.5-1.5 h to obtain a first mixture;

(2) Uniformly mixing the foaming agent and the first mixture through a static mixer to obtain a second mixture;

(3) And (3) mixing and foaming the second mixture and the organic polyisocyanate in proportion through a high-pressure gun head at the temperature of 20+/-3 ℃ and controlling the gun head pressure to be 110-150 bar to prepare the rigid polyurethane foam.

Comparative example 9

100 parts of polyol composition, 2.1 parts of foam catalyst, 2.2 parts of foam stabilizer, 2.1 parts of water, 12.5 parts of foaming agent-pentane and 151 parts of organic polyisocyanate.

The preparation method of the rigid polyurethane foam was the same as that of comparative example 8, except that the preparation of the rigid polyurethane foam was carried out according to the above formulation.

Comparative example 10

100 parts of a polyol composition, 2.1 parts of a foam catalyst, 2.2 parts of a foam stabilizer, 2.2 parts of water, 12.5 parts of a foaming agent-pentane, 7 parts of a foaming agent-HFO-1336 mzz, 2 parts of a foaming agent-n-butane and 153 parts of organic polyisocyanate.

Comparative example 11

100 parts of polyol composition, 2.1 parts of foam catalyst, 2.2 parts of foam stabilizer, 2.2 parts of water, 12.5 parts of foaming agent-pentane and 7 parts of foaming agent-HFO-1336 mzz and 151 parts of organic polyisocyanate.

Example 17

The embodiment provides a rigid polyurethane foam and a preparation method thereof, and specifically comprises the following steps:

100 parts of polyol composition, 2.1 parts of foam catalyst, 2.2 parts of foam stabilizer, 1.9 parts of water, 16 parts of foaming agent-pentane, 3.0 parts of foaming auxiliary agent-trifluoropropene and 150 parts of organic polyisocyanate.

(2) Uniformly mixing a foaming agent, a foaming auxiliary agent and the first mixture through a static mixer to obtain a second mixture;

Example 18

100 parts of polyol composition, 2.1 parts of foam catalyst, 2.2 parts of foam stabilizer, 2.1 parts of water, 13.5 parts of foaming agent-pentane, 7 parts of foaming agent-HFO-1233 zd, 2.0 parts of trifluoropropene and 155 parts of organic polyisocyanate.

The rigid polyurethane foam was prepared in the same manner as in example 17, except that the rigid polyurethane foam was prepared in accordance with the above-described formulation.

Example 19

100 parts of polyol composition, 2.1 parts of foam catalyst, 2.2 parts of foam stabilizer, 2.2 parts of water, 13.5 parts of foaming agent-pentane, 7 parts of foaming agent-HFO-1336 mzz, 2.0 parts of foaming auxiliary agent-trifluoropropene and 155 parts of organic polyisocyanate.

[ Performance test ]

The present disclosure is directed to the rigid polyurethane foam prepared in the above comparative examples and examples, and the free foam density, average thermal conductivity (10 ℃,0 ℃), average compressive strength, dimensional stability and other performance tests were respectively performed, and specific test results are shown in the following table:

table 8 raw material ratios and foam properties of examples and comparative examples

As can be seen from the data in Table 8, compared with the comparative examples, the rigid polyurethane foam prepared by the formulation and the preparation method provided by the present disclosure has the advantages of smaller heat conductivity, better heat insulation performance, lower dimensional deformation rate and good foam mechanical property. After the molding core density of the foam is greatly reduced, the compression strength of the foam is similar, and the comprehensive performance is excellent. Therefore, the density of the hard polyurethane foam core provided by the disclosure can be as low as about 26.76kg/m < 3 >, so that the raw material filling amount can be reduced, and meanwhile, the good comprehensive performance can be still maintained, and the requirements of refrigerator manufacturers are met. Therefore, under the same technological parameters, the polyurethane foam prepared by adopting the foam composition formula provided by the disclosure can effectively reduce the raw material pouring quantity and the foam density, thereby achieving the purpose of reducing the production cost. And (3) injection: the performance test criteria in table 8 are as follows:

Free bubble density, molded core density: density testing of GB/T6343-95 polyurethane foam.

Compressive strength: measurement of compression Properties of GB/T8813-2008 rigid foam.

Thermal conductivity coefficient: GB/T10295-2008 heat insulating material steady state thermal resistance and related characteristic measurement heat flow meter method.

Dimensional stability: measurement of linear dimensions of GB/T8811-2008 foam and rubber.

[ Hard polyurethane foam complete machine energy consumption test on 300L refrigerator-freezer products ]

The present disclosure further conducted energy-saving testing of the rigid polyurethane foam obtained in example 17 and comparative example 8 on 300L refrigerator-freezer products, the results of which are shown in Table 9.

Table 9 energy consumption test data for whole body

The performance test of the whole machine is measured according to Chinese standards (GB/T8059-2016 household and similar-purpose refrigerating appliances and GB 12021.2-2015 household refrigerator power consumption limit values and energy efficiency grades), and table data show that compared with comparative example 8, the whole machine energy consumption of the refrigerator product adopting some embodiments of the present disclosure is reduced by 3.24%, and the load temperature rise time is improved by 16.39%. Meanwhile, the polyurethane foams of the example 17 and the comparative example 8 are subjected to electron microscopy (as shown in fig. 1-2), and as can be seen from the figures, the rigid polyurethane foam prepared by the method has finer foam and finer and uniform foam cells.

Based on the results of tables 8 and 9 and fig. 2, the present disclosure can make the prepared foam cells finer by introducing trifluoropropene with good environmental protection and compounding with the foaming system commonly used at present, can better solve the defect of high thermal conductivity when a cyclopentane independent system is used, reduces the density and thermal conductivity of polyurethane rigid foam, and can solve the problems that butane type low-boiling point foaming system cannot improve the thermal conductivity of foam, and HFC-134a and HFC-152a type low-boiling point foaming systems have high GWP values and are not friendly to the environment. The method for preparing the rigid polyurethane foam by using the composition disclosed by the invention is particularly suitable for refrigerator and freezer products, and can better realize the environment protection, energy saving and resource saving of the refrigerator and freezer products.

The disclosure also provides a thermal insulation material prepared from the low density rigid polyurethane foam according to any of the embodiments above.

The disclosure also provides a refrigerator comprising the heat insulation material prepared from the low-density rigid polyurethane foam.

The present disclosure also provides an ice bin comprising a thermal insulation material prepared from the low density rigid polyurethane foam described above.

It should be noted that the above embodiments are only for illustrating the technical solutions of the present disclosure and not for limiting the scope of the present disclosure, and although the present disclosure has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present disclosure without departing from the spirit and scope of the technical solutions of the present disclosure.

In the description of the present disclosure, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "longitudinal", "X-axis direction", "Y-axis direction", "Z-axis direction", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present disclosure and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present disclosure. Also, some of the terms described above may be used to indicate other meanings in addition to orientation or positional relationships, for example, the term "upper" may also be used to indicate some sort of attachment or connection in some cases. The specific meaning of these terms in this disclosure will be understood by those of ordinary skill in the art as appropriate.

The foregoing is merely a preferred embodiment of the present disclosure, and it should be noted that modifications and substitutions will now occur to those skilled in the art without departing from the technical principles of the present disclosure, and these modifications and substitutions should also be considered to be within the scope of the present disclosure.

Claims

A polyurethane foam comprising: an organic polyisocyanate and a white stock composition;

The white material composition comprises the following components in parts by weight:

The composite foaming agent consists of a high-boiling point fluoroolefin foaming agent with a boiling point of more than or equal to 5 ℃ and a low-boiling point fluoroolefin foaming agent with a boiling point of less than or equal to-15 ℃, wherein the high-boiling point fluoroolefin foaming agent is 25-35 parts, and the low-boiling point fluoroolefin foaming agent is 1-3 parts.
The polyurethane foam according to claim 1, wherein the weight ratio of the high boiling point fluoroolefin blowing agent to the low boiling point fluoroolefin blowing agent is (12 to 15) to 1.
The polyurethane foam according to claim 1 or 2, wherein, the high boiling point fluoroolefin foaming agent is 1-chloro-3, 3-trifluoropropene cis-1, 4-hexafluoro-2-butene at least one of trans-1, 4-hexafluoro-2-butene.
The polyurethane foam according to any one of claim 1 to 3, wherein, the low-boiling point fluoroolefin foaming agent is 3, 3-trifluoropropene, trans-1, 3-tetrafluoropropene at least one of 2, 3-tetrafluoropropene and 1,2, 3-pentafluoropropene.
The polyurethane foam according to any one of claims 1 to 4, wherein the high boiling point fluoroolefin blowing agent in the composite blowing agent is cis-1, 4-hexafluoro-2-butene and the low boiling point fluoroolefin blowing agent is 3, 3-trifluoropropene.
The polyurethane foam of any one of claims 1 to 5, wherein the polyol composition comprises a polyether polyol and/or a polyester polyol; the average functionality of the polyether polyol is more than or equal to 3.5, and the hydroxyl value is 330-480 mgKOH/g; the average functionality of the polyester polyol is 2.8-3, and the hydroxyl value is 250-350mgKOH/g.
The polyurethane foam according to any one of claims 1 to 6, satisfying at least one of the following (a) to (c):

(a) The foam stabilizer is an organosiloxane polyoxyalkylene graft copolymer;

(b) The catalyst comprises a foaming catalyst, a gel catalyst and a trimerization catalyst;

(c) The organic polyisocyanate is polymethylene polyphenyl polyisocyanate.
The polyurethane foam of any one of claims 1 to 7, wherein the weight ratio of the white stock composition to organic polyisocyanate is 1: (1.08-1.3).
A process for producing the polyurethane foam as claimed in any one of claims 1 to 8, comprising:

mixing the polyol composition, water, foam stabilizer and catalyst at 20-30 ℃ to obtain a first mixture;

Mixing the first mixture and the high-boiling point fluoroolefin foaming agent through static premixing equipment at 15-20 ℃ and under the pressure of 1.0-2.5 MPa to obtain a second mixture;

mixing the second mixture and the low-boiling point fluoroolefin foaming agent through static premixing equipment at 15-20 ℃ and under the pressure of 2.5-4.0 MPa to obtain a third mixture, namely a white material composition;

And mixing and foaming the white material composition and the organic polyisocyanate in proportion through a high-pressure foaming gun head, wherein the gun head pressure is 110-160 bar, and the polyurethane foam material is prepared.
A refrigerator comprising a shell, an inner container and a heat insulation layer arranged between the shell and the inner container, wherein the heat insulation layer is made of the polyurethane foam material as claimed in any one of claims 1 to 8.
An ice chest comprising a shell, an inner container and a heat insulation layer arranged between the shell and the inner container, wherein the heat insulation layer is made of the polyurethane foam material as claimed in any one of claims 1 to 8.