CN110628073A - Formula and preparation method of polyurethane rigid foam - Google Patents

Abstract

The invention discloses a polyurethane hard foam formula and a preparation method thereof, and relates to the technical field of polyurethane materials. The polyurethane hard foam is prepared by mixing polyphenyl polymethylene polyisocyanate, combined polyether and a plurality of foaming agents; the formula of the polyurethane rigid foam comprises the following components in parts by weight: 125-155 parts of polyphenyl polymethylene polyisocyanate, 100 parts of combined polyether and 14-20 parts of various foaming agents. The invention combines a foaming agent with high boiling point, a foaming agent with medium boiling point and a foaming agent with low boiling point, namely n-butane and/or isobutane, into a new foaming agent, and then the new foaming agent is mixed with polyphenyl polymethylene polyisocyanate and combined polyether to prepare rigid polyurethane foam; the foaming density and the foaming cost of the polyurethane rigid foam can be effectively reduced; the polyurethane rigid foam has good dimensional stability and low heat conductivity coefficient; in addition, the polyurethane rigid foam has zero OPD value and low GWP value, and is suitable for domestic and foreign markets.

Description

Formula and preparation method of polyurethane rigid foam

Technical Field

The invention belongs to the technical field of polyurethane materials, and particularly relates to a formula of polyurethane rigid foam and a preparation method thereof.

Background

The polyurethane rigid foam has excellent heat insulation performance and bearing strength, is widely applied to industries such as household appliances, building boards, pipeline refrigeration and heat insulation, and the like, and the heat conductivity coefficient of the polyurethane rigid foam is an important parameter for measuring the heat insulation performance of the foam. The heat conductivity coefficient mainly comprises foam gas phase heat conduction, solid phase heat conduction, radiation heat conduction and the like, wherein the gas phase heat conduction is determined by the type and the using amount of the foaming agent, the solid phase heat conduction is determined by the foam body and is difficult to change, and the radiation heat conduction is determined by the size and the shape of the foam hole and is mainly influenced by the type of the foaming agent and the foaming process.

The national requirement on energy consumption of the household appliance industry is higher and higher, and at present, a refrigerator mainly adopts a mixed foaming mode of cyclopentane and 245fa (1,1,1,3, 3-pentafluoropropane) to replace an original cyclopentane foaming system. In order to reduce the foaming cost, the foaming density of a refrigerator reaches a bottleneck by continuously improving a cyclopentane/245 fa mixed foaming technology in recent years, and if the foaming density is further reduced, a low-boiling point foaming agent needs to be adopted, and the low-boiling point foaming agent which is inherently used in the industry at present is mainly 134a (1,1,1, 2-tetrafluoroethane).

However, since the GWP of the third generation blowing agent such as 245fa and 134a is high, the GWP has been already put under the restriction of the Kyoto protocol, and the use of the blowing agent has been restricted in the countries of the European Union, so that the combined GWP of the household refrigerator and the refrigerator is required to be less than or equal to 150, and the use of HFC-type substances containing high GWP of 245fa and 134a is prohibited in the household refrigerator and the refrigerator since 2020 in the United states. In order to meet the requirements of regulations, 245fa and 134a foaming agents must be replaced in domestic export refrigerators at present, and if 245fa and 134a are respectively replaced by LBA (trans-1-chloro-3, 3, 3-trifluoropropene) and 152a (1, 1-difluoroethane) foaming agents, the foaming cost is increased more, and great cost pressure is brought to the production of the refrigerators; if original cyclopentane is replaced for foaming, not only the heat conductivity coefficient of the foam is increased, which is not beneficial to the requirement of improving the energy efficiency, but also the comprehensive cost is increased more, which is not preferable.

Therefore, there is a need to develop a rigid polyurethane foam formulation that meets the regulatory requirements and reduces the foaming cost.

Disclosure of Invention

The invention aims to provide a polyurethane hard foam formula, which solves the problems that the existing polyurethane hard foam does not conform to the regulation due to overhigh GWP, the preparation cost of the polyurethane hard foam is high and the performance is poor by combining a plurality of high, medium and low boiling point foaming agents into a new foaming agent and mixing the new foaming agent with polyphenyl polymethylene polyisocyanate and combined polyether.

In order to solve the technical problems, the invention is realized by the following technical scheme:

the invention relates to a formula of rigid polyurethane foam, wherein the rigid polyurethane foam is prepared by mixing polyphenyl polymethylene polyisocyanate, combined polyether and a plurality of foaming agents;

the formula of the polyurethane rigid foam comprises the following components in parts by weight: 125-155 parts of polyphenyl polymethylene polyisocyanate, 100 parts of combined polyether and 14-20 parts of various foaming agents;

further, the various foaming agents comprise 9-16 parts of pentane, 1-4 parts of butane and 2-7 parts of 1,1,1,3, 3-pentafluoropropane or trans-1-chloro-3, 3, 3-trifluoropropene;

further, 11-14 parts of pentane, 2-3 parts of butane and 4-5 parts of 1,1,1,3, 3-pentafluoropropane or trans-1-chloro-3, 3, 3-trifluoropropene.

Further, the pentane is one of cyclopentane and cyclopentane isopentane or the mixture of cyclopentane and cyclopentane is (6-9): (4-1).

Further, the butane is one or two of normal butane and isobutane.

Further, the combined polyether comprises 100 parts of polyether polyol and/or polyester polyol composition, 2-3 parts of foam stabilizer, 1.5-2.5 parts of catalyst and 1.5-2.4 parts of water.

Further, 100 parts of polyether polyol and/or polyester polyol composition, 2.5-2.8 parts of foam stabilizer, 1.9-2.2 parts of catalyst and 1.9-2.1 parts of water.

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

step one, premixing a foaming agent: pumping n-butane and isobutane into a mixing tank through a metering pump under the pressure of 5-15 bar, and stirring for 20min to form a butane premix;

step two, preparing a mixed white material: the method comprises the following steps of (1) preparing a premixed material of the composite polyether, pentane and butane, and 1,1,1,3, 3-pentafluoropropane or trans-1-chloro-3, 3, 3-trifluoropropene through a quaternary static mixer, and maintaining the pressure of the prepared mixed white material in a charging bucket, wherein the pressure value of the pressure maintaining is 3-6 bar;

step three, foaming: and (2) injecting the polyphenyl polymethylene polyisocyanate and the mixed white material into a foaming cavity through high-pressure foaming equipment, and carrying out milky-white, foaming and crosslinking on the liquid raw material until the liquid raw material is completely cured so as to form a rigid polyurethane foam product.

The invention has the following beneficial effects:

the invention combines a new foaming agent by using cyclopentane and isopentane serving as high-boiling foaming agents, 1,1,1,3, 3-pentafluoropropane or trans-1-chloro-3, 3, 3-trifluoropropene serving as medium-boiling foaming agents and n-butane and/or isobutane serving as low-boiling foaming agents, and then the new foaming agent is mixed with polyphenyl polymethylene polyisocyanate and combined polyether to prepare the polyurethane rigid foam; the foaming density and the foaming cost of the polyurethane rigid foam can be effectively reduced, and the consumption of foaming materials is saved; the polyurethane rigid foam has good dimensional stability and low heat conductivity coefficient, and ensures the dimensional stability and the heat insulation performance of the polyurethane rigid foam; in addition, the polyurethane rigid foam has zero OPD value and low GWP value, and is suitable for domestic and foreign markets.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

A polyurethane hard foam formula, the polyurethane hard foam is prepared by mixing polyphenyl polymethylene polyisocyanate, combined polyether and a plurality of foaming agents;

the formula of the polyurethane rigid foam comprises the following components in parts by weight: 125-155 parts of polyphenyl polymethylene polyisocyanate, 100 parts of combined polyether and 14-20 parts of various foaming agents;

wherein the multiple foaming agents comprise 9-16 parts of pentane, 1-4 parts of butane and 2-7 parts of 1,1,1,3, 3-pentafluoropropane or trans-1-chloro-3, 3, 3-trifluoropropene;

wherein, pentane is 11-14 parts, butane is 2-3 parts, 1,1,1,3, 3-pentafluoropropane or trans-1-chloro-3, 3, 3-trifluoropropene is 4-5 parts; 1,1,1,3, 3-pentafluoropropane or trans-1-chloro-3, 3, 3-trifluoropropene belong to the medium-boiling blowing agents;

wherein the pentane is one of cyclopentane and cyclopentane isopentane or the mixture of cyclopentane and cyclopentane isopentane is (6-9): (4-1); cyclopentane and cyclopentane are high-boiling blowing agents.

Wherein, the butane is one or two of normal butane and isobutane; n-butane and isobutane belong to the low-boiling blowing agents.

Wherein, the combined polyether comprises 100 parts of polyether polyol and/or polyester polyol composition, 2-3 parts of foam stabilizer, 1.5-2.5 parts of catalyst and 1.5-2.4 parts of water.

Wherein, 100 portions of polyether polyol and/or polyester polyol composition, 2.5 to 2.8 portions of foam stabilizer, 1.9 to 2.2 portions of catalyst and 1.9 to 2.1 portions of water.

The preparation method comprises the following steps of combining a high-boiling point foaming agent cyclopentane and cyclopentane, a medium-boiling point foaming agent 1,1,1,3, 3-pentafluoropropane or trans-1-chloro-3, 3, 3-trifluoropropene and a low-boiling point foaming agent n-butane and/or isobutane into a new foaming agent, and mixing the new foaming agent with polyphenyl polymethylene polyisocyanate and combined polyether to prepare the polyurethane hard foam; the foaming density and the foaming cost of the polyurethane rigid foam can be effectively reduced, and the consumption of foaming materials is saved; the polyurethane rigid foam has good dimensional stability and low heat conductivity coefficient, and ensures the dimensional stability and the heat insulation performance of the polyurethane rigid foam; in addition, the polyurethane hard foam has zero OPD value (ozone depletion potential 2) and low GWP value (global warming potential), is suitable for domestic and foreign markets and conforms to European and American regulations.

The polyether polyol and/or polyester polyol compositions employed in the examples of the present invention consist of:

polyether A: phenylenediamine polyether polyol with the functionality of 4 and the hydroxyl value of 390-430 mgKOH/g;

polyether B: glycerol polyether polyol, the functionality is 3, the hydroxyl value is 320-370 mgKOH/g;

polyether C: sucrose polyether polyol with functionality of 6-7 and hydroxyl value of 370-410 mgKOH/g;

polyether D: sorbitol polyether polyol with functionality of 6, hydroxyl value of 410-480 mgKOH/g;

polyester E: the phthalic anhydride polyester polyol has the functionality of 2-3 and the hydroxyl value of 300-330 mgKOH/g.

In the embodiment of the invention, the catalyst is a tertiary amine and/or metal salt catalyst, and is generally compounded by three catalysts, namely an opal catalyst, a gel catalyst and a trimerization catalyst, wherein the opal catalyst is preferably pentamethyldiethylenetriamine, the gel catalyst is preferably one or two of dimethylcyclohexylamine, triethylenediamine and dibutyltin dilaurate, and the trimerization catalyst is preferably 1,3, 5-tris (dimethylaminopropyl) -hexahydrotriazine;

in the embodiment of the invention, the foam stabilizer is silicone oil and mainly plays a role in stabilizing foam pores.

In the embodiment of the present invention, polyphenyl polymethylene polyisocyanate, also called polymeric MDI, commonly called crude MDI, is preferably one or more of Wanhua PM200, Wanhua PM2010, Kostewa 44V20L, Pasteur M20s, Hensman 5005, etc., and the NCO content is 30.5-32%.

According to the invention, the density, the compressive strength, the heat conductivity coefficient and the dimensional stability of the foam are respectively measured according to national standards GB/T6343-2009, GB/T8813-2008, GB/T10295-2008 and GB/T8811-2008, the size of a square mould for preparing the foam is 800 multiplied by 500 multiplied by 100mm, the volume of a refrigerator for preparing the foam is 253L, when in foaming, a material liquid is injected into the mould through a foaming machine, and the rigid polyurethane foam is obtained after foaming, curing and forming.

The amounts of the respective components of the raw materials used in examples 1 to 4 and comparative examples 1 to 2 are shown in Table 1.

Table 1:

raw material dosage	Unit of	Example 1	Example 2	Example 3	Example 4	Comparative example 1	Comparative example 2
								Polyether A	Parts by weight	40	40	35	35	40	35
Polyether B	Parts by weight	15	15	10	10	15	10
								Polyether C	Parts by weight	20	20	25	25	20	25
Polyether D	Parts by weight	15	15	20	20	15	20
								Polyether E	Parts by weight	10	10	5	5	10	5
Catalyst and process for preparing same	Parts by weight	2.1	2.1	1.9	1.9	2.0	1.8
								Foam stabilizer	Parts by weight	2.8	2.8	2.8	2.8	2.8	2.6
Water (W)	Parts by weight	2.1	2.1	2.0	2.0	2.1	2.1
								Cyclopentane	Parts by weight	12	12	9.5	9.5	12	9.5
Cycloisopentane	Parts by weight	/	/	4	4	/	4
								245fa	Parts by weight	4	/	2	/	4	2
LBA	Parts by weight	/	4	/	2	/	/
								N-butane	Parts by weight	1	1	1	1	/	/
Isobutane	Parts by weight	1	1	1	1	/	/
								Polymeric MDI	Parts by weight	150	150	149	149	147.4	146.4

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

step one, premixing a foaming agent: pumping n-butane and isobutane into a mixing tank through a metering pump under the pressure of 5-15 bar, and stirring for 20min to form a butane premix;

step two, preparing a mixed white material: the method comprises the following steps of (1) preparing a premixed material of the composite polyether, pentane and butane, and 1,1,1,3, 3-pentafluoropropane or trans-1-chloro-3, 3, 3-trifluoropropene through a quaternary static mixer, and maintaining the pressure of the prepared mixed white material in a charging bucket, wherein the pressure value of the pressure maintaining is 3-6 bar;

step three, foaming: injecting polyphenyl polymethylene polyisocyanate and mixed white material into a foaming cavity through high-pressure foaming equipment, and performing milky white, foaming and crosslinking on liquid raw materials until the liquid raw materials are completely cured to form a hard polyurethane foam product; this step can be foamed according to the process requirements specified for the foaming process.

After the prepared polyurethane rigid foam is cured for 2 hours, performance tests such as foam core density, compressive strength, thermal conductivity coefficient, dimensional stability and the like are carried out;

the results of the tests of examples 1-4 and comparative examples 1-2 are shown in Table 2.

Table 2:

as shown in Table 2, it can be seen from the comparison between examples 1-4 and comparative examples 1-2 that the introduction of low-boiling point foaming agents, namely n-butane and isobutane, can significantly reduce the density of the foam core, and the core density can be reduced by 5-6%, which is beneficial to reducing the use amount of foaming materials, thereby reducing the foaming cost; in the aspect of compressive strength, the compressive strength of the foam of the examples is basically unchanged while the density of the foam is reduced, mainly because the boiling point of a butane foaming agent is low, the saturated vapor pressure of gas is large, the compressive strength of the foam is high, and the dimensional stability of the foam at low temperature is good.

As shown in Table 2, the foam thermal conductivity of example 2 using LBA blowing agent is lower than that of comparative example 1, and the thermal conductivity of example 1 using 245fa blowing agent is substantially equivalent.

The results of comparative tests on the BCD-253 refrigerator foaming test of example 2 and comparative example 1 are shown in Table 3

Table 3:

as can be seen from table 3, compared with comparative example 1, the density of the foam core of the foaming layer of the refrigerator prepared in example 2 is 28.97Kg/m3, and the density difference is 0.95, which shows that after the butane foaming agent is added, the foam fluidity is obviously improved, the injection amount is reduced by 5.9%, the curing time is reduced by 50s, not only the foaming cost of the refrigerator can be reduced, but also the foaming efficiency is improved, and the economic benefit is obvious; in addition, in the aspects of manufacturability such as foam surface bubbles, back bubble bulge, adhesion and the like, the processing performance of the embodiment 2 is basically equivalent to that of the comparative example 1, only the back bulge is slightly increased, and the improvement can be realized by optimizing the formula of the foaming material.

The refrigerator foaming layer prepared in the embodiment 2 has zero ODP value and less than 10 GWP value, is more environment-friendly and can meet the requirements of advanced countries such as Europe and America on HFCs substances.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed.

Claims (7)

1. The formula of the rigid polyurethane foam is characterized in that: the rigid polyurethane foam is prepared by mixing polyphenyl polymethylene polyisocyanate, combined polyether and a plurality of foaming agents;

the formula of the polyurethane rigid foam comprises the following components in parts by weight: 125-155 parts of polyphenyl polymethylene polyisocyanate, 100 parts of combined polyether and 14-20 parts of various foaming agents;

the foaming agents comprise 9-16 parts of pentane, 1-4 parts of butane and 2-7 parts of 1,1,1,3, 3-pentafluoropropane or trans-1-chloro-3, 3, 3-trifluoropropene.

2. The rigid polyurethane foam formulation of claim 1, wherein said pentane is present in an amount of 11 to 14 parts, said butane is present in an amount of 2 to 3 parts, and said 1,1,1,3, 3-pentafluoropropane or trans-1-chloro-3, 3, 3-trifluoropropene is present in an amount of 4 to 5 parts.

3. The rigid polyurethane foam formula according to claim 1, wherein the pentane is one of cyclopentane and cyclopentane or the cyclopentane and the cyclopentane are mixed according to the ratio of (6-9): (4-1).

4. The rigid polyurethane foam formulation according to claim 1, wherein the butane is one or both of n-butane and isobutane.

5. The rigid polyurethane foam formulation according to claim 1, wherein the polyether composition comprises 100 parts of polyether polyol and/or polyester polyol composition, 2-3 parts of foam stabilizer, 1.5-2.5 parts of catalyst and 1.5-2.4 parts of water.

6. The rigid polyurethane foam formulation and the process for preparing the same as claimed in claim 1, wherein the polyether polyol and/or polyester polyol composition comprises 100 parts, 2.5-2.8 parts, 1.9-2.2 parts and 1.9-2.1 parts of water.

7. The process for preparing a rigid polyurethane foam according to any one of claims 1 to 6, comprising the steps of:

step one, premixing a foaming agent: pumping n-butane and isobutane into a mixing tank through a metering pump under the pressure of 5-15 bar, and stirring for 20min to form a butane premix;

step two, preparing a mixed white material: the method comprises the following steps of (1) preparing a premixed material of the composite polyether, pentane and butane, and 1,1,1,3, 3-pentafluoropropane or trans-1-chloro-3, 3, 3-trifluoropropene through a quaternary static mixer, and maintaining the pressure of the prepared mixed white material in a charging bucket, wherein the pressure value of the pressure maintaining is 3-6 bar;

step three, foaming: and (2) injecting the polyphenyl polymethylene polyisocyanate and the mixed white material into a foaming cavity through high-pressure foaming equipment, and carrying out milky-white, foaming and crosslinking on the liquid raw material until the liquid raw material is completely cured so as to form a rigid polyurethane foam product.