CN114805907B

CN114805907B - Foaming agent, isocyanate-reactive composition and polyurethane foam

Info

Publication number: CN114805907B
Application number: CN202210585397.XA
Authority: CN
Inventors: 邢益辉; 张蒙蒙; 傅振华; 江芸
Original assignee: Nanjing Hongbaoli Polyurethane Co ltd; Hongbaoli Group Co ltd
Current assignee: Nanjing Hongbaoli Polyurethane Co ltd; Hongbaoli Group Co ltd
Priority date: 2022-03-16
Filing date: 2022-05-27
Publication date: 2023-12-08
Anticipated expiration: 2042-05-27
Also published as: CN114805907A

Abstract

The application discloses a foaming agent, which contains neopentane, wherein the neopentane accounts for at least 1.2mol% of the foaming agent. The application also discloses an isocyanate-reactive composition prepared by using the foaming agent and polyurethane foam containing the foaming agent. By using the application, the process operability can be further improved on the premise of not improving the filling quantity and not reducing the filling effect.

Description

Foaming agent, isocyanate-reactive composition and polyurethane foam

Technical Field

The application belongs to the technical field of chemistry, and particularly relates to a foaming agent, a composition for reacting with isocyanate and polyurethane foam.

Background

The hard polyurethane foam has good heat preservation and insulation performance, and is one of key factors for energy conservation and emission reduction of household appliances such as refrigerators and freezers. The lower the heat conductivity coefficient of the rigid polyurethane foam is, the better the heat preservation and insulation performance is, the more energy loss caused by heat exchange can be reduced, and the energy saving of the household appliance is facilitated. For household appliances such as refrigerators, the hard polyurethane foam in the refrigerator is obtained through a dynamic reaction process from a liquid phase to a solid phase, so that the energy-saving effect of the household appliances is directly affected by the good or bad filling effect, and the filling has a short plate effect, namely, the cold and heat exchange cannot be effectively slowed down as long as one place is not completely filled, and finally the energy consumption of the household appliances is increased.

In order to improve the filling effect of polyurethane foaming stock solution on the inner cavity of the interlayer of the refrigerator, particularly on the complex cavity structure, an overfilling mode is usually adopted, but the more the filling amount is, the more the resource consumption is, and the raw material cost input is also increased. In order to achieve both a small amount of injected materials and a good filling effect, a low boiling point substance with a boiling point less than zero such as butane is generally used as one of the components of the foaming agent, but the low boiling point substance such as butane has poor compatibility with materials, a small maximum addition amount and high gasification speed, so that the defects of large metering fluctuation and poor process operability exist, uncontrollable factors are increased in the continuous production process, the quality of the rigid polyurethane foam is unstable, particularly the influence on the surface condition of the foam is more remarkable, large cells are easily generated on the surface of the polyurethane foam if the operation process is improper, the outer layer of the refrigerator is recessed or swelled, the appearance of the refrigerator is influenced, and the back plate material is corroded.

Therefore, further improvement of process operability without increasing the filling amount and without reducing the filling effect is still a problem to be solved in the art.

Disclosure of Invention

The technical problems to be solved by the application are as follows: the process operability is further improved without increasing the filling amount and reducing the filling effect.

In order to achieve the above object, the present application provides a blowing agent comprising at least neopentane as a component; when the blowing agent comprises at least two components, the molar ratio of neopentane in the blowing agent is at least 1.2mol%. The compatibility between the pentane foaming agent and polyurethane reaction raw materials is good, the use amount is large, the operation is easy, the pentane foaming agent used in the field of rigid polyurethane foam is usually cyclopentane, n-pentane and isopentane, the inventor of the application unexpectedly discovers in the research that the polyurethane foaming reaction is carried out under the condition that neopentane exists, and the process operability can be further improved. The neopentane is close to a spherical molecular structure, so that the intermolecular acting force is smaller, the uniform release of the foaming agent is facilitated, the continuous and stable polyurethane reaction process is ensured, and the stability of the foam surface condition is further facilitated. Preferably, the neopentane accounts for 1.2 to 96.6mol% of the foaming agent. In the present application, mol% means mole percent.

The blowing agent in the present application may be a single component blowing agent formed from one component of neopentane or a multi-component blowing agent formed from neopentane with other blowing agents and/or adjuvants, i.e., the multi-component blowing agent comprises neopentane and other blowing agents, or the multi-component blowing agent comprises neopentane and adjuvants, or the multi-component blowing agent comprises neopentane, other blowing agents and adjuvants.

Other blowing agents means blowing agents other than neopentane, which may be selected from physical blowing agents and/or chemical blowing agents known in the art, which may be selected from alkanes, fluoroolefins, hydrofluorocarbons, carbon dioxide, alcohols containing 1 to 5 carbon atoms, aldehydes containing 1 to 4 carbon atoms, ethers or diethers containing 1 to 4 carbon atoms, organic acids or organic acid esters, wherein alkanes preferably have a boiling point of-45 to 100 ℃, such as cyclopentane, isopentane, n-pentane, n-butane, isobutane, cyclohexane, propane, n-hexane and its isomers, n-heptane and its isomers, etc., the fluoroolefins means fluoroolefins unsubstituted by halogen atoms or fluoroolefins substituted by halogen atoms, preferably monofluoropropene, difluoropropene, trifluoropropene, tetrafluoropropene, pentafluoropropene, hexafluoropropene, monofluorobutene, difluorobutene, trifluorobutene, tetrafluorobutene, pentafluorobutene, hexafluorobutene, heptafluorobutene, octafluorobutene, octafluoropentene or difluoroethylene, etc., the fluoroolefins substituted by halogen atoms means hydrogen on carbon atoms being substituted by one or several halogens such as trifluoropropene substituted by chlorine, tetrafluoropropene substituted by chlorine, etc.; the hydrofluorocarbon compound may be selected from pentafluoropropane, pentafluorobutane, difluoroethane or tetrafluoroethane, etc.; the chemical blowing agent known in the art may be selected from materials capable of participating in the reaction during the foaming process and generating carbon dioxide or other gases, preferably water, organic ammonium salt compounds containing carbon dioxide donor anions, etc., and is typically mixed with polyol, etc. to form a composition capable of reacting with isocyanate, and then reacted with physical blowing agent, isocyanate to prepare polyurethane foam, but the present application does not exclude the use of the blowing agent described in the present application by mixing the chemical blowing agent with neopentane or with neopentane, physical blowing agent, etc., i.e., the blowing agent described in the present application may contain chemical blowing agent known in the art, or may not contain chemical blowing agent known in the art.

When the foaming agent comprises neopentane and other foaming agents, the other foaming agents are preferably at least one of alkane compounds, fluoroolefin compounds or hydrofluorocarbon compounds, so as to achieve the performances of process operability, surface condition, bending strength, heat preservation, heat insulation and the like, and the molar ratio of the other foaming agents to the foaming agents is more preferably 25.3-97.9 mol%.

Preferably, the other foaming agent is cyclopentane, preferably the molar ratio of cyclopentane to the foaming agent is 33.9-74.5 mol%. The inventor of the application unexpectedly found in the research that when cyclopentane and neopentane are matched for use, the boiling point distribution range of the foaming agent is wider, so that the phenomena of escape of the foaming agent and centralized release of the foaming agent are reduced, and therefore, the generation of large foam holes can be reduced, the surface condition of the polyurethane foam can be further improved on the basis of ensuring the operability of the process, the adhesion between the rigid polyurethane foam and a refrigerator liner is further improved, and the quality fluctuation of the rigid polyurethane foam obtained by continuous production is smaller under the same production process condition, and the surface condition is kept in a good state continuously.

It is also preferable that the other blowing agent is a hydrofluorocarbon compound, and the inventors of the present application have unexpectedly found in the study that when the hydrofluorocarbon compound is used in combination with neopentane, the cell wall strength can be further enhanced, and a rigid polyurethane foam is given a better flexural strength, thereby improving the endurance of the polyurethane foam in environmental changes and improving the structural stability of the polyurethane foam product. Further, 1, 3-pentafluoropropane is preferably used as the hydrofluorocarbon compound, so that both high and low temperature dimensional stability and high flexural strength can be achieved.

It is also preferable that the other foaming agent is a fluoroolefin compound, and the molar ratio of the fluoroolefin foaming agent to the foaming agent is preferably 14.2-26.9 mol%, so as to achieve both low cost and excellent heat preservation and insulation performance. In order to compromise the availability of the raw materials, the fluoroolefin foaming agent is trans-1-chloro-3, 3-trifluoropropene, trans-1, 3-tetrafluoropropene, 2, 3-tetrafluoropropene 1,2, 3-pentafluoropropene, hexafluoropropylene at least one of 1, 4-hexafluoro-2-butene or cis-1-chloro-2, 3-tetrafluoropropene.

When the foaming agent comprises neopentane and an auxiliary agent, the auxiliary agent can be a surfactant, a flame retardant, a catalyst, a nucleating agent, a solubilizer, a filler, a colorant and the like or other substances inert to the neopentane reaction, wherein the surfactant is a substance capable of reducing the surface tension of liquid, and the surfactant is preferably an organosilicon surfactant in order to achieve the compatibility between the components of the material. In order to improve the uniformity of neopentane dispersion and obtain foam with better comprehensive performance, the auxiliary agent is preferably at least one of a surfactant, a flame retardant, a catalyst or a nucleating agent, and the auxiliary agent is preferably a nucleating agent, wherein the nucleating agent is preferably at least one of perfluoroolefin, fluorine-containing ether and perfluoroalkyl amine, and the proportion of the nucleating agent in the foaming agent is preferably 0.4-3.4 mol%. Wherein the perfluoroolefin may be selected from hexafluoropropylene, hexafluoropropylene dimer, hexafluoropropylene trimer, perfluoro-1-hexene, perfluoro-1-butene, perfluoro-2-butene, perfluorobutadiene, perfluoro-2-methyl-2-pentene, perfluoro-4-methyl-2-pentene, perfluorocyclopentene, perfluoro-1-heptene, perfluorobutylethylene, perfluorocyclohexane, octafluorocyclobutane or perfluoro-1, 2-dimethylcyclohexane, the fluorine-containing ether is selected from the group consisting of nonafluoroisobutyl methyl ether, nonafluorobutyl ethyl ether, nonafluoroisobutyl ethyl ether, difluoroethyl tetrafluoroethyl ether, difluoromethyl trifluoroethyl ether, bis (trifluoroethyl) ether, tetrafluoroethyl ethyl ether, tetrafluoroethyl propyl ether, tetrafluoroethyl difluoromethyl ether, tetrafluoroethyl tetrafluoropropyl ether, octafluoropentyl tetrafluoroethyl ether heptafluoromethyl propyl ether, 1, 3-pentafluoro-2-trifluoromethyl propyl methyl ether, perfluorobutyl methyl ether, 2-difluoroethyl trifluoromethyl ether, trifluoromethyl trifluorovinyl ether, perfluoropropyl vinyl ether, 1, 3-hexafluoroisopropyl methyl ether, 2, 3-pentafluoropropyl methyl ether or 2, 2-trifluoroethyl methyl ether, the perfluoroalkyl amine is preferably perfluoro tributylamine or perfluoro triethylamine. Further preferably, the surface tension of the nucleating agent is < 15mN/m to obtain a better nucleating effect.

Further, in order to compromise the synergistic effect between neopentane and other blowing agents, and neopentane and adjuvants, more preferably the blowing agents include neopentane, other blowing agents and adjuvants.

Next, the present application also provides a composition capable of reacting with isocyanate comprising a polyol composition and a blowing agent as described in any of the above. The isocyanate-reactive composition refers to a mixture capable of chemically reacting with isocyanate and forming polyurethane foam, and the composition generally includes polyol, catalyst, foam stabilizer, blowing agent, water, auxiliary agent, etc., wherein the polyol, catalyst, foam stabilizer, water, auxiliary agent, etc. are generally mixed to form a polyol composition, and then mixed with all or part of the blowing agent to form an isocyanate-reactive composition, and the polyol, catalyst, foam stabilizer, auxiliary agent, etc. in the polyol composition may be any of those known in the art, wherein the polyol may be polyether polyol, polyester polyol, polycarbonate polyol, bio-based polyol, and hydroxyl-containing substances such as small molecule polyol including 1, 4-butanediol. When the foaming agent is used for producing the polyurethane foam, the process operability of the polyurethane foam can be optimized, the surface condition of the polyurethane foam can be improved, and the quality stability of the polyurethane foam can be improved. Further, in order to achieve both the process suitability of the polyurethane foam, it is preferable that the isocyanate-reactive composition contains 30.1wt% at most of the blowing agent, and in order to achieve both low cost and excellent performance, it is further preferable that the isocyanate-reactive composition contains 7.4 to 30.1wt% of the blowing agent, and it is further preferable that the isocyanate-reactive composition is composed of 18.7 to 24.0wt% of the blowing agent and 76.0 to 81.3wt% of the polyol composition.

Finally, the application provides a polyurethane foam which contains the foaming agent disclosed by the application, wherein the weight of the foaming agent accounts for 3.1-15.4 wt% of the total weight of the polyurethane foam, and the weight of the foaming agent is more preferably 8.9-11.8 wt%. The polyurethane foam prepared by using the foaming agent comprises, but is not limited to, closed cell foam, open cell foam, semi-open cell foam and the like, the foam form of the polyurethane foam can be rigid, soft or semi-rigid, and the polyurethane foam is preferably prepared by using the foaming agent, so that the rigid polyurethane foam has lower density, better dimensional stability, better energy saving and consumption reduction of refrigerator products, better process operability, and is easy to control and operate in the production process, thereby ensuring the stability of the quality of continuously produced foam.

The rigid polyurethane foam of the present application may be produced by reacting an isocyanate with the isocyanate-reactive composition of the present application, or by reacting an isocyanate with a polyol composition known in the art and the blowing agent of the present application. The raw materials of the rigid polyurethane foam are preferably: 35.8 to 39.7wt% of polyol composition, 3.1 to 15.4wt% of blowing agent, 48.7 to 57.8wt% of isocyanate, more preferably 37.4 to 38.6wt% of polyol composition, 8.9 to 11.8wt% of blowing agent, 50.8 to 52.5wt% of isocyanate.

The preparation method of the rigid polyurethane foam of the application is realized by adopting the known technology in the field, and the following three modes are preferable:

mode one: uniformly stirring and mixing a foaming agent, a polyol composition and isocyanate at a high speed, and then carrying out polyurethane reaction;

mode two: premixing a polyol composition and a foaming agent, and then uniformly mixing the polyol composition and isocyanate through high-speed stirring, and carrying out polyurethane reaction;

mode three: dividing a foaming agent into two parts, wherein one part of the foaming agent is premixed with isocyanate to form an isocyanate mixture, the other part of the foaming agent is premixed with a polyol composition to form a composition reacting with isocyanate, and then uniformly stirring and mixing the composition reacting with isocyanate and the isocyanate mixture at a high speed, and carrying out polyurethane reaction;

in the preparation method, the first mode and the second mode are conventional, so that the use convenience is realized, the mobility of the reaction raw materials in the process of filling the cavity can be further improved, the foam density can be reduced, and the raw material cost can be saved. In addition, the auxiliary agents such as nucleating agents may be used to prepare the rigid polyurethane foam by forming a multi-component blowing agent together with the blowing agent, or may be used to prepare the rigid polyurethane foam by adding the auxiliary agents to the polyol composition and/or isocyanate.

The isocyanate used in the present application may be polymethylene polyphenyl polyisocyanate (abbreviated as polymeric MDI), toluene diisocyanate (abbreviated as TDI), modified isocyanate, or the like, as is known in the art, and when two or more isocyanates are selected, a mixture of them in any ratio may be used. Among these, polymeric MDI preferably has an average functionality of 2.7 to 2.9 to give consideration to the thermal conductivity of polyurethane rigid foam. The polymeric MDI having an average functionality of 2.7 may be selected fromPM200、/>44v20L、/>M20s、/>The polymeric MDI of average functionality of 2.9 may be selected from any of PM2010M50、/>PM400、/>44V40L、/>2085. The industrial TDI is usually a mixture of 2, 4-toluene diisocyanate and 2, 6-toluene diisocyanate, and TDI-65, TDI-80, TDI-100, etc. can be used in the present application depending on the mass ratio of 2, 4-toluene diisocyanate in the mixture. The modified isocyanate is a substance prepared by reacting polyol with isocyanate, wherein the polyol can be polyether polyol taking glycerol, glycol, diethylene glycol, pentaerythritol and the like as an initiator, or phthalic anhydride polyester polyol, or bio-based polyol. The bio-based polyol is a polyol compound prepared from soybean oil, castor oil, rapeseed oil, jatropha curcas oil, olive oil, palm oil or derivatives thereof, such as castor oil polyol, olive oil polyol, palm oil polyol, castor oil derivative polyol, etc.

Overall, the overall advantages of the application are: on the premise of not improving the filling quantity and not reducing the filling effect, better process operability is obtained, namely, under the same process condition, the surface condition fluctuation of the rigid polyurethane foam obtained by continuous production is small, and the product quality stability is good. Meanwhile, the rigid polyurethane foam obtained by the application has better foam performance, and has the advantages of uniform density distribution, low heat conductivity coefficient, high specific strength, good dimensional stability, high bending strength and the like.

The specific embodiment is as follows:

for a better understanding of the present application, the following examples are further illustrated, but are not limited to the following examples. The application prepares rigid polyurethane foam according to the following steps:

and mixing the foaming agent and the polyol composition in a closed container to obtain a composition reacting with isocyanate, mixing the composition reacting with isocyanate and isocyanate through high-pressure foaming machine equipment, injecting the mixture into a mould for foaming, and curing to obtain the polyurethane foam, wherein the overfill amount is 12%. Wherein, the overfill refers to the percentage of the actual charge that exceeds the minimum charge.

The mold for checking the filling effect, the density distribution uniformity and the surface condition is a Lanzhi mold with a stop block, and the specific method is as follows: the Lanzhi mold having an inner cavity size of 20cm (length) ×5cm (width) ×200cm (height) was placed vertically, i.e., the height direction was the vertical direction. Adding three check blocks into a blue sesame mould, wherein the sizes of the check blocks I and II are the same, the check blocks I and II are 15cm (length) multiplied by 5cm (width) multiplied by 5cm (height), the check block III is 20cm (length) multiplied by 2.5cm (width) multiplied by 10cm (height), the check block I is arranged at a position 120cm away from the bottom of the blue sesame mould and is attached to the left side surface of the inner cavity of the blue sesame mould, the check block II is arranged at a position 130cm away from the bottom of the blue sesame mould and is attached to the right side surface of the inner cavity of the blue sesame mould, and the check block III is arranged at a position 150cm away from the bottom of the blue sesame mould and is attached to the rear side surface of the inner cavity of the blue sesame mould. And (3) injecting polyurethane foaming stock solution into the inner cavity from a material injection port at the bottom of the Lanzhi mold, taking out foam after curing, and inspecting the filling effect, the density distribution uniformity and the surface condition.

The filling effect is divided into five levels, namely that the cavity of the Lanzhi mould is completely filled and has no cavity, and the filling effect is good; four levels indicate that voids with diameters less than 5mm only occur around the stop; three-level indicates that a cavity with the diameter of 5-10 mm only appears around the stop block, and the filling effect is general; the second level shows that the hollow with the diameter larger than 10mm only appears around the stop block, and the filling effect is poor; the first level indicates that the cavity of the Lanzhi mold is not completely filled.

The density distribution uniformity is expressed by adopting a sample standard deviation of core density, the detection method is to sample every 20cm from bottom to top along the height direction of the Lanzhi mould, 9 samples are obtained in total, and the sample standard deviation of the core density of the 9 samples is calculated.

The surface condition is that the size and the number of cavities visible to naked eyes on the surface of the hard polyurethane foam after demolding are that the size of the cavities is more than or equal to 1cm, the size of the cavities is more than or equal to 0.5cm and less than or equal to 1cm, the size of the cavities is more than or equal to 0.5cm, the size of the cavities is more than or equal to C, and if the number of the cavities is more than or equal to 1, the surface condition is poor; if the number of the class A cells is 0, the number of the class B cells is less than or equal to 3 and the number of the class C cells is less than or equal to 6, the surface condition is good; the rest is that the surface condition is general. The cell diameter as referred to herein means the largest diameter of the cells.

The process operability in the application adopts the fluctuation condition of the surface condition as a measurement index, if the fluctuation of the surface condition of a plurality of polyurethane foams obtained by continuous material injection is smaller, the process operability is considered to be good, and if the fluctuation of the surface condition of a plurality of polyurethane foams obtained by continuous material injection is larger, the process operability is considered to be bad. The main investigation method is as follows: under the same technological condition, 10 blue sesame molds with a stop block are continuously filled by using the same gun head, and the blue sesame molds are sequentially marked as mold-1, mold-2, mold-3, mold-4, mold-5, mold-6, mold-7, mold-8, mold-9 and mold-10, and the change condition of the surface condition of the hard polyurethane foam in the 10 blue sesame molds is recorded.

The core density, the dimensional stability, the heat conductivity and the compressive strength are all carried out according to the method in GB/T26689-2011 hard polyurethane foam plastics for refrigerators and freezers, the bending strength is carried out according to the rule in GB/T8812.2-2007 determination of bending property of hard foam plastics at the 2 nd part and determination of apparent bending elastic modulus, the sample is cuboid, the length (120+/-1.20) mm, the width (25+/-0.25) mm and the thickness (20+/-0.20) mm, the span between two brackets is (100+/-1.0) mm, and the test speed is (10+/-2) mm/min.

The polyol composition used in the present application has an average hydroxyl value of 404mgKOH/g and is composed of the following substances in weight percentage: 37.0wt% sucrose polyether polyol (hydroxyl value 373-395 mgKOH/g), 23.0wt% sorbitol polyether polyol (hydroxyl value 485-515 mgKOH/g), 23.0wt% glycerin polyether polyol (hydroxyl value 320-350 mgKOH/g), 9.0wt% toluene diamine polyether polyol (hydroxyl value 380-450 mgKOH/g), 3.5wt% composite catalyst, 2.5wt% foam stabilizer and 2.0wt% water.

The foaming agents listed in the application are foaming agents 1# to 15#, but the application is not limited to the listed material range, and the specific material composition is as follows:

the blowing agent # 1 was 53.5 mole% neopentane and 46.5 mole% cyclopentane;

the blowing agent # 2 was 25.3 mole% neopentane, 69.4 mole% cyclopentane and 5.3 mole% n-butane;

the 3# blowing agent was 4.3 mole% neopentane, 74.5 mole% cyclopentane and 21.2 mole% isopentane;

the # 4 blowing agent was 36.1 mole% neopentane, 49.7 mole% cyclopentane and 14.2 mole% trans-1, 4-hexafluoro-2-butene;

the blowing agent # 5 was 8.1 mole% neopentane, 67.1 mole% cyclopentane and 24.8 mole% trans-1-chloro-3, 3-trifluoropropene;

the # 6 blowing agent was 45.3 mole% neopentane, 33.9 mole% cyclopentane, 10.4 mole% 2, 3-tetrafluoropropene and 10.4 mole% trans-1, 3-tetrafluoropropene;

the 7# blowing agent was 2.0 mole% neopentane, 70.7 mole% cyclopentane, 25.5 mole% cis-1-chloro-2, 3-tetrafluoropropene and 1.8 mole% trifluoromethyl trifluorovinyl ether;

the 8# blowing agent was 1.2 mole% neopentane, 71.0 mole% cyclopentane, 26.9 mole% trans-1-chloro-3, 3-trifluoropropene, 0.5 mole% perfluoro-4-methyl-2-pentene and 0.4 mole% perfluorotriethylamine;

the blowing agent # 9 was 66.4 mole% neopentane, 33.2 mole% isopentane and 0.4 mole% perfluoropropyl vinyl ether;

the 10# blowing agent was 25.1 mole% neopentane, 68.8 mole% cyclopentane, 5.2 mole% n-butane, 0.5 mole% perfluoro-1-heptene and 0.4 mole% perfluorotributylamine;

11# blowing agent 24.7mol% neopentane, 71.9mol% cyclopentane, 1.4mol% perfluorocyclopentene and 2.0mol%2, 2-difluoroethyl trifluoromethyl ether;

the No. 12 foaming agent is neopentane;

the # 13 blowing agent was 12.2 mole% neopentane and 87.8 mole% 1, 3-pentafluoropropane;

the # 14 blowing agent was 74.7 mole% neopentane and 25.3 mole% trans-1-chloro-3, 3-trifluoropropene;

the 15# blowing agent was 96.6 mole% neopentane and 3.4 mole% perfluoropropyl vinyl ether

The foaming agent for comparison of the application comprises the following specific components:

the D-1# foaming agent is cyclopentane;

the D-2# foaming agent is 83mol percent of cyclopentane and 17mol percent of isopentane;

the D-3# foaming agent is 87.6mol percent of cyclopentane and 12.4mol percent of n-butane;

the D-4# blowing agent was 76.4mol% cyclopentane, 23.1mol% trans-1-chloro-3, 3-trifluoropropene and 0.5mol% perfluorotributylamine;

the D-5# blowing agent was 70.1mol%1, 3-pentafluoropropane, 26.4mol% trans-1-chloro-3, 3-trifluoropropene, 3.5mol% perfluoropropyl vinyl ether.

The isocyanate used in the present application was a polymeric MDI with an average functionality of 2.7.

The preparation of the rigid polyurethane foam was carried out in accordance with the material ratios in the following table, and the properties of the obtained rigid polyurethane foam were characterized, and the results are shown in tables 1 and 2.

Table 1 results of characterization of the proportions of materials and foam properties for examples 1-10

Table 2 results of characterization of the proportions of the materials and foam properties for examples 11-16 and comparative examples

As can be seen from the data in tables 1 and 2, the surface conditions, density distribution uniformity, dimensional stability, specific strength (i.e., ratio of compressive strength to density), and flexural strength of the inventive examples 1 to 16 were all better than those of the comparative examples, indicating that the inventive polyurethane foam had superior overall properties. The overall performance of comparative example was poor, in which, although the filling effect of comparative example 3 was comparable to that of the present example, the surface condition was general, and since the maximum addition amount of butane was lower than that of neopentane, it was difficult to further lower the core density of comparative example 3 in the binary foaming system used in combination with cyclopentane, resulting in relatively high raw material cost. In addition, it can be seen from example 13 and comparative example 1 that at the same density level, the polyurethane foam prepared with pure neopentane had better properties than the polyurethane foam prepared with pure cyclopentane. Comparative example 2 the performance of the rigid polyurethane foam prepared by using a mixed foaming system of cyclopentane and isopentane was inferior to that of the rigid polyurethane foam prepared in examples 1 and 3 according to the present application, namely, the rigid polyurethane foam prepared by using a mixed foaming agent composed of other pentane-based foaming agents and cyclopentane was also inferior to that of the rigid polyurethane foam prepared by using neopentane and cyclopentane as the mixed foaming agents according to the present application.

Meanwhile, although the foam properties of examples 12 and 13 are good, the use of neopentane alone, because of its limited maximum addition, also causes problems of higher core density and increased raw material cost, and therefore, it is recommended to use neopentane in combination with other foaming agents. As can be seen from examples 1 to 11 and examples 14 to 16, when a combination blowing agent containing neopentane is used, the core density of the polyurethane foam prepared is 27 to 28kg/m ³ The foaming agent or the composition reacting with isocyanate can realize excellent performance under the condition, so that the foaming agent or the composition reacting with isocyanate can give consideration to the foam performance on the premise of not improving the filling quantity and not reducing the filling effect, and has the convenience of process operation.

The application also characterizes the surface condition fluctuation conditions of the examples and the comparative examples, and the results are shown in Table 3.

TABLE 3 fluctuation of surface conditions

Mould-1

Mould-2

Mould-3

Mould-4

Mould-5

Mould-6

Mould-7

Mould-8

Mould-9

Mould-10

Example 1

Good (good)

In general

Good (good)

Example 3

Good (good)

In general

Good (good)

Example 7

Good (good)

In general

Good (good)

In general

Good (good)

Example 10

Good (good)

In general

Good (good)

In general

Example 12

Good (good)

In general

Good (good)

Example 13

Good (good)

In general

Good (good)

Example 14

Good (good)

In general

Good (good)

Example 15

Good (good)

In general

Good (good)

In general

Good (good)

Example 16

Good (good)

In general

Good (good)

In general

Comparative example 1

In general

Difference of difference

In general

Difference of difference

In general

Comparative example 2

In general

Difference of difference

In general

Difference of difference

In general

Difference of difference

Comparative example 3

In general

Difference of difference

In general

Difference of difference

In general

Difference of difference

In general

Difference of difference

Comparative example 4

In general

Difference of difference

In general

Difference of difference

In general

Difference of difference

In general

Comparative example 5

In general

Difference of difference

In general

Difference of difference

In general

Difference of difference

In general

As can be seen from the data in the table, the surface conditions of the embodiments of the present application perform better overall than the comparative examples, and can be kept at a good level, and the surface conditions of the embodiments of the present application fluctuate less, and other embodiments of the present application have the same effects, and are not described herein. In the continuous material injection process, the surface conditions of the comparative examples 1-5 are poor, the surface conditions are poor for many times, the fluctuation frequency is high, mainly because the foaming systems used in the comparative examples 1,2 and 4-5 are easy to generate the phenomenon of concentrated release of the foaming agent, the butane in the foaming system of the comparative example 3 is poor in dispersibility, and the foaming agent of the application can be uniformly released in the foaming reaction process, so that the whole reaction can be stably carried out, and finally, the stable product quality is obtained, therefore, the foaming agent, the composition or the polyurethane foam adopted by the application do not need frequent adjustment of the production conditions, and has good process operability.

Claims

1. The foaming agent is characterized by comprising at least two components, wherein the mole ratio of the neopentane in the foaming agent is at least 1.2-96.6 mol%, the foaming agent is a multi-component foaming agent formed by the neopentane and other foaming agents and/or auxiliary agents, the other foaming agent is alkane compound, hydrofluorocarbon compound, trans-1, 3-tetrafluoropropene at least one of 2, 3-tetrafluoropropene, 1,2, 3-pentafluoropropene, hexafluoropropene or 1, 4-hexafluoro-2-butene, the auxiliary agent is a nucleating agent, and the nucleating agent is at least one of perfluoroolefin, fluorine-containing ether or perfluoroalkyl amine;

the alkane compound is at least one of cyclopentane, isopentane or n-butane;

the hydrofluorocarbon compound is selected from pentafluoropropane, pentafluorobutane, difluoroethane or tetrafluoroethane;

the other foaming agents account for 25.3-97.9mol% of the foaming agents;

the nucleating agent accounts for 0.4-3.4mol% of the foaming agent;

the sum of the mole percentages of the components of the foaming agent is 100 percent.

2. The blowing agent of claim 1 wherein the blowing agent comprises neopentane and other blowing agents, the other blowing agents being an alkane compound, the alkane compound being at least one of cyclopentane, isopentane or n-butane.

3. The foaming agent according to claim 2, wherein the other foaming agent accounts for 25.3-97.9mol% of the foaming agent.

4. The blowing agent of claim 1 wherein said blowing agent comprises neopentane and a nucleating agent.

5. The foaming agent according to claim 4, wherein the nucleating agent accounts for 0.4-3.4 mol% of the foaming agent.

6. The blowing agent of claim 2 wherein said blowing agent comprises an auxiliary agent.

7. An isocyanate-reactive composition comprising a polyol composition and the blowing agent of any of claims 1 to 6.

8. The isocyanate-reactive composition of claim 7, wherein the blowing agent comprises 7.4 to 24wt% based on the total weight of the isocyanate-reactive composition.

9. A polyurethane foam comprising the blowing agent according to any one of claims 1 to 6 in cells of the polyurethane foam.