WO2020221204A1

WO2020221204A1 - Low-density rigid polyurethane foam and preparation method therefor

Info

Publication number: WO2020221204A1
Application number: PCT/CN2020/087230
Authority: WO
Inventors: 邢益辉; 吴一鸣; 熊丽媛
Original assignee: 红宝丽集团股份有限公司
Priority date: 2019-04-29
Filing date: 2020-04-27
Publication date: 2020-11-05
Also published as: CN110054752B; CN110054752A

Abstract

Disclosed is a low-density rigid polyurethane foam, which is prepared by pre-mixing separately a component A and a component B, then mixing same together and foaming, wherein in parts by weight, the component A comprises: (1) 100 parts of a composite polyol; (2) 5-15 parts of cyclopentane; (3) 1.5-6 parts of an amine catalyst; (4) 1-5 parts of a silicon surfactant; and (5) 0.8-2.5 parts of water; the component B comprises: (1) 1-10 parts of butane; and (2) 120-220 parts of isocyanate. The raw materials are based on 100 parts of the composite polyol. The preparation method comprises the following steps: (1) preparing a component A; (2) preparing a component B; (3) injecting the component A and the component B into a closed mold, fully reacting, and demolding to obtain a rigid polyurethane foam. By means of the technology, a low-density rigid polyurethane foam which is environmentally-friendly and has excellent performance is prepared.

Description

Low-density rigid polyurethane foam and preparation method thereof

Technical field

The invention relates to a low-density rigid polyurethane foam and a preparation method thereof, and more specifically, to a low-density rigid polyurethane foam using cyclopentane and butane as blowing agents and a preparation method thereof

Background technique

Rigid polyurethane foam (hereinafter referred to as rigid foam) is made of polyisocyanate and polyol through addition polymerization in the presence of catalysts and other additives. It has excellent thermal insulation performance, sound insulation, insulation, light weight, and High strength, good processing performance, etc., are widely used as thermal insulation materials. In order to achieve better thermal insulation effect, a certain amount of physical foaming agent with low boiling point and low thermal conductivity must be added to the foam material. Unfortunately, the traditional polyurethane foaming agent-fluorotrichloromethane (CFC-11) can severely destroy the ozone layer. After the signing of the "Montreal Protocol" in 1987, countries have started researches on CFC-11 replacement foaming agents. After the signing of the "Kyoto Protocol" in 1997, people began to focus on protecting the ozone layer and reducing the greenhouse effect at the same time, hoping to develop a new type of blowing agent with zero ozone depletion potential (ODP) and zero global warming potential (GWP) to cope with the global increase Serious environmental problems.

Compared with halogenated hydrocarbon foaming agents, alkane foaming agents (such as pentane, butane, etc.) have no halogen atoms, ODP is zero, and GWP is approximately zero. They are environmentally friendly and relatively inexpensive, making them ideal One of the alternatives to foaming agents.

Among alkane foaming agents, cyclopentane is the most used, which has been widely used in household appliances, building insulation, container industries and other fields. It is worth noting that the boiling point of cyclopentane is as high as 49℃, so it is easy to condense in low temperature environment, and cyclopentane has plasticity. The condensed cyclopentane will have a certain swelling effect on the foam, resulting in foam deformation and dimensional stability. Poor sex. In order to ensure that the cyclopentane foam has sufficient mechanical strength to cope with this deformation, technicians generally increase the foam density by increasing the amount of feed, thereby improving the dimensional stability of the foam, which will undoubtedly increase the production cost. Butane has poor solubility in polyols, is rarely used in polyurethane rigid foams, and has a low boiling point. Among them, the boiling point of n-butane is -0.5°C and that of isobutane is -11.73°C. They have more requirements on the operation process. Strictly, they are easy to quickly escape from the reaction material during foaming, resulting in increased pores on the foam surface, which will adversely affect the foam performance.

The traditional method for preparing rigid polyurethane foam is to premix the blowing agent and the composite polyol, and then react with the polyisocyanate to prepare the foam. The disadvantages of this process method are: the low boiling point foaming agent has limited solubility in the polyol, the actual process operation is difficult, the foaming agent easily escapes from the reaction solution, resulting in increased foam density and increased surface pores. The foam performance is poor.

Summary of the invention

The invention aims to solve the shortcomings of the existing cyclopentane foaming technology, and firstly provides a low-density rigid polyurethane foam that is environmentally friendly and has excellent performance.

The specific technical solutions are:

A low-density rigid polyurethane foam, which is prepared by mixing component A and component B uniformly in advance, then mixing component A and component B, mechanically mixing uniformly, and foaming; wherein, parts by weight meter,

Component A includes:

(1) Compound polyol, 100 parts, hydroxyl value 250～550mg KOH/g;

(2) Cyclopentane, 5-15 parts;

(3) Amine catalyst, 1.5-6 parts;

(4) Silicone surfactant, 1-5 parts;

(5) Water, 0.8～2.5 parts;

Combination B includes:

(1) Butane, 1-10 parts;

(2) Isocyanate, 120～220 parts;

All the above raw materials are based on 100 parts of composite polyol. That is, the raw materials for preparing the low-density rigid polyurethane foam are based on 100 parts of composite polyol.

In this application, cyclopentane and butane are used as co-blowing agents, cyclopentane and composite polyol are mixed to form component A, butane and isocyanate are mixed to form component B, and then the two components are fully processed Mixing reaction to prepare low-density polyurethane foam. Compared with the traditional preparation process, the technical solution of this application can reduce the stable density of the foam (that is, the minimum density when the dimensional stability of the foam meets the requirements), and can also increase the maximum allowable addition amount of alkane foaming agent in the reaction material system Therefore, compared with the cyclopentane foaming system (the amount of cyclopentane in the general hard foam formulation for refrigerators is about 14 parts by weight, and the amount of water is about 2 parts by weight), this application can reduce the amount of water to 0.8 parts by weight. As is well known to those skilled in the art, the urea group formed by the reaction of isocyanate with water is brittle, which makes the dimensional stability of the foam worse, and the bonding performance of the substrate deteriorates; at the same time, the CO ₂ gas phase thermal conductivity generated by the reaction of the _two Too high will result in high thermal conductivity of the foam and unsatisfactory thermal insulation performance.

This application has discovered that the viscosity of the isocyanate will increase after modification, which will not be conducive to the processing and mixing between component A and component B, but adding a certain amount of butane can effectively reduce the viscosity of component B, so that Component B can maintain good processing properties.

In the component A, the composite polyol is at least one of polyether polyol, polyester polyol, vegetable oil-based polyol or polycarbonate polyol. By weight, 100 parts of composite polyol include: 0-100 parts of ether polyols with a hydroxyl value of 120-600mg KOH/g, 0-100 parts of polyester polyols with a hydroxyl value of 100-450 mg KOH/g, and 0-40 parts of vegetable oil-based polyols with a hydroxyl value of 350 ~650mg KOH/g, 0-20 parts of polycarbonate polyol and a hydroxyl value of 30-450mg KOH/g.

The hydroxyl value decreases, the molecular chain lengthens, and the foam strength decreases. In this way, the foam density needs to be increased to achieve the specified strength. On the contrary, if the hydroxyl value is too high, the molecular chain is too short, the foam is brittle, easy to break, and the adhesion between the foam and the substrate becomes poor.

Furthermore, in the above-mentioned low-density rigid polyurethane foam,

The polyether polyol is formed by reacting an active hydrogen initiator and an alkylene oxide, wherein the alkylene oxide is selected from at least one of propylene oxide, ethylene oxide or butylene oxide. The active hydrogen initiator is selected from compounds containing active hydrogen, such as: sucrose, glycerol, trimethylolpropane, pentaerythritol, sorbitol, xylitol, mannitol, methyl glucose, ethylenediamine, triethanolamine or toluene One or a mixture of two or more diamines.

Ethylene oxide is beneficial to improve the compatibility of polyols and water, butene oxide can improve the compatibility of polyols and cyclopentane, and propylene oxide plays a role of balance and compatibility.

In the above-mentioned low-density rigid polyurethane foam, the polyester polyol is selected from aliphatic polyester polyols and/or aromatic polyester polyols, and the polyester polyols are formed by the condensation of low molecular weight alcohols and low molecular weight acids (anhydrides). The low-molecular alcohol can be selected from at least one of ethylene glycol, diethylene glycol, propylene glycol, glycerol or trimethylolpropane; the low-molecular acid (anhydride) can be selected from maleic anhydride and diethylene glycol. At least one of acid, phthalic anhydride, phthalic acid, and phthalic acid ester.

Polyols containing benzene ring structure are helpful to improve foam strength and thermal conductivity. However, in general, they have high viscosity and high activity, and the amount in the formulation is limited, especially in the foaming formulation in the complex cavity.

In the above low-density rigid polyurethane foam, in the component B, butane is n-butane or isobutane, or a mixture of n-butane and isobutane in any ratio.

Compared with cyclopentane, butane has a relatively low boiling point, which can make the foam still have good cell pressure at low temperatures, can significantly improve the low-temperature dimensional stability of the foam, and reduce the density of the foam in the cyclopentane foaming system. Then reduce the cost of foam.

In the above low-density rigid polyurethane foam, the amine catalyst in the component A is selected from the group consisting of pentamethyldiethylenetriamine, dimethylbenzylamine, dimethylcyclohexylamine, and N-methylbicyclic Hexylamine, triethylenediamine, tetramethylethylenediamine, tetramethylhexamethylenediamine, N-methylimidazole, 1,2-dimethylimidazole, bis(dimethylaminoethyl)ether, dimethyl Ethanolamine, triethanolamine, 1,3,5-tris(dimethylaminopropyl)-hexahydrotriazine, 2,4,6-tris(dimethylaminomethyl)phenol and 2-hydroxypropyltrimethyl Any two or a mixture of two or more of the ammonium carbamate salts.

The above-mentioned catalyst can ensure the stable progress of the reaction balance through compounding.

In the above-mentioned low-density rigid polyurethane foam, the mass fraction of the isocyanate group (NCO) of the isocyanate in the component B is 16.0%-31.0%.

1. Modified isocyanate can improve its compatibility with polyols-polyols are more polar and generally prefer water solubility, while unmodified isocyanates are oil-soluble, and the compatibility between the two is poor.

2. It can improve the stability of the reaction, and the activity of the NCO after modification will decrease, and more catalysts can be added to the reaction system to promote the improvement of foam production efficiency.

In the above-mentioned low-density rigid polyurethane foam, the isocyanate is a modified isocyanate that can be obtained by prepolymerizing an isocyanate reactant and isocyanate, wherein the functionality of the isocyanate reactant is 2 to 3, and the isocyanate reactant is selected From at least one of polycarbonate diol, polyester polyol, or polyether polyol.

By modifying the isocyanate, the reaction activity of the polyisocyanate is reduced, and the reaction is promoted to proceed smoothly, thereby improving the overall performance of the foam; more catalysts can be added to the reaction system to greatly improve the production efficiency of the foam. Research has also found that the application of modified isocyanates can improve the compatibility of isocyanates and polyols. However, the viscosity of the isocyanate increases after modification, which is not conducive to the processing and mixing between component A and component B, and the presence of butane in component B in the technical scheme of this application can effectively reduce the viscosity of component B. The fluidity of component B is equivalent to that of component A, so that component B can maintain good processing performance and improve the fluidity of the reaction liquid, thereby increasing the foam strength and reducing the amount of filling.

In the aforementioned low-density rigid polyurethane foam, the polycarbonate polyol in the isocyanate reactant is selected from polycarbonate polyols with a hydroxyl value of 30-400 mg KOH/g, and the polyether polyol is selected from a hydroxyl value of 200- 500mg KOH/g polyether polyol, polyester polyol is selected from polyester polyols with a hydroxyl value of 150-400 mg KOH/g.

Using the isocyanate reactant of the present application to modify the isocyanate can not only improve the compatibility between the isocyanate and the polyol, but also ensure that the foam has sufficient mechanical strength, which is beneficial to reduce the stable density of the foam.

In the above-mentioned low-density rigid polyurethane foam, the polycarbonate polyol in the isocyanate reactant is formed by the reaction of carbon dioxide and alkylene oxide, wherein the alkylene oxide is selected from at least one of propylene oxide, ethylene oxide or butylene oxide Kind.

The molecular structure of carbonate polyols contains a large number of carbonyl groups, and the intermolecular cohesion energy is large, which can bring excellent mechanical properties to foam materials, increase foam strength and reduce the stable density of foam, but its high viscosity will cause The viscosity of the reaction material increases significantly and the operability decreases. When polycarbonate polyol is used in component A, the present invention improves the operability and mechanical mixing performance by increasing the temperature of component A. Generally, the amount of carbonate polyol in component A is 0-20 parts by weight. When the polycarbonate polyol modified isocyanate is used in component B, butane is added to component B to reduce the viscosity of component B and improve the operating performance of component B.

In the above low-density rigid polyurethane foam, the silicon surfactant in the component A can be specifically selected from commercially available ones, such as Niax L-6884, Niax L-6988; Niax L-6863 from Momentive , Niax L-6891, Niax L-6988, Niax L-6952, etc.; AK8860, AK8863, AK8805, AK8810, AK8818, AK8830, etc. of Mestel.

Those of ordinary skill in the art can also add optional other additives at the same time or separately as needed to obtain better performance, for example, anti-aging agents, plasticizers, preservatives, fungicides, nucleating agents, and antistatic agents , Flame retardants, smoke inhibitors, crosslinkers, pigments, fillers, etc.

Secondly, this application also provides a method for preparing the above-mentioned low-density rigid polyurethane foam, which includes the following steps:

(1) Preparation of component A: add the composite polyol, cyclopentane, amine catalyst, silicon surfactant and water into the mixing kettle according to the set ratio, stir evenly to obtain component A, and control the material temperature to 25~ 41℃;

(2) Preparation of component B: deliver butane and isocyanate to the mixer according to the set ratio, mix evenly to obtain component B, and control the material temperature to 5-20°C;

(3) Mixed injection: Mix component A and component B into a closed mold through a high-pressure machine gun head, and fully react. The mold temperature is controlled at 35～50℃, and the foaming material is overfilled in the mold with a coefficient of 105%～135. %, the rigid polyurethane foam can be obtained after demolding.

In the production of rigid polyurethane foam, when the temperature of the reaction material is low, the viscosity of the material is high, and the mixing effect during foaming is poor; when the temperature of the reaction material is high, the viscosity of the material is low, and the mixing effect during foaming is improved, but the temperature of the reaction material is high It will cause the foaming reaction speed to be greatly accelerated, and affect the filling performance in the complex cavity. In addition, if the temperature is too high, the low-boiling foaming agent will vaporize quickly, and the material will rise too fast, which will easily form a large cavity inside the foam and cause foam defects.

At the same operating temperature, the escape rate of the foaming agent and the fluidity of the material are not matched for the component A containing cyclopentane and the component B containing butane. The foaming effect becomes worse after the two are mixed, causing The foam performance decreases. In the present invention, the material temperature of component A containing cyclopentane is controlled to 25～41℃, and the material temperature of component B containing butane is controlled to 5～20℃, by strictly limiting the material temperature of each component It can effectively exert the synergy between different foaming agents, especially between different foaming agents with large boiling point differences. Increase the material temperature of component A and lower the material temperature of component B, so that the mixing effect of the two is better, and the reaction between the two proceeds smoothly, which can effectively slow down the escape rate of butane, improve the foam performance, and reduce the foam surface The pores make the foam maintain good dimensional stability at low temperatures, thereby effectively reducing the amount of pouring and the density of the foam.

Compared with the prior art, the present invention has the following characteristics:

1. The rigid polyurethane foam prepared by the invention has uniform density distribution, high specific strength, good dimensional stability at low temperatures, can effectively reduce the amount of perfusion, lower costs, and produce low-density foam;

2. The present invention reduces the material liquid temperature of component B by improving the preparation process, which can greatly reduce the surface porosity of the foam and improve the surface performance of the foam;

3. The rigid polyurethane foam prepared by the invention has fine cells, low thermal conductivity, and good thermal insulation performance;

4. The present invention can reduce the weight of water in the formula and prepare rigid polyurethane foam with excellent thermal insulation performance and good mechanical properties;

5. The rigid polyurethane foam prepared by the present invention uses cyclopentane and butane as physical foaming agents, ODP is zero, GWP is extremely low, and is environmentally friendly.

Detailed ways

In order to better understand the present invention, the content of the present invention will be described in further detail below in conjunction with the embodiments. The embodiments described here are only used to illustrate and explain the present invention, and are not used to limit the present invention. If specific techniques or conditions are not indicated in the embodiments, it can be carried out according to well-known techniques in the art.

The density, thermal conductivity, compression strength, expansion rate, and high and low temperature dimensional change rate of the foam in the present invention are respectively in accordance with the national standards GB/T 6343-2009, GB/T 3399-1982, GB/T 8813-2008, GB/T 20673 -2006, GB/T8811-2008, the overall density refers to the foam forming composition is injected into a closed mold (1200×400×70mm) with a certain strength to foam, after the foam is formed and taken out, the measured foam density.

In the following examples, the low-density rigid polyurethane foam is produced according to the following steps:

(2) Prepare component B: deliver butane and isocyanate to the mixer according to the set ratio, mix evenly to obtain component B, and control the material temperature to 5-20°C;

(3) Mixed injection: mix component A and component B into a closed mold (1200×400×70mm) according to the set ratio through a high-pressure machine gun head, fully react, the mold temperature is controlled at 35～50℃, and the foam material The overfill coefficient in the mold is 105% to 135%, and low-density rigid polyurethane foam can be obtained after demolding.

Part of the parameters not involved in each specific embodiment and comparative example are listed in Table 1 and Table 2.

The parts in the following examples and comparative examples are parts by weight, and in each example, 100 parts of the composite polyol are used as a reference.

Example 1

Component A: The material and liquid temperature is 35°C,

Compound polyol: hydroxyl value of 430mgKOH/g, 100 parts, including:

Polyether polyol A: sucrose polyether polyol, the hydroxyl value is 450～530mgKOH/g, 40 parts;

Polyether polyol B: glycerin polyether polyol, the hydroxyl value is 200～300mgKOH/g, 30 parts;

Polyether polyol C: sorbitol polyether polyol, the hydroxyl value is 400～480mgKOH/g, 30 parts;

Amine catalyst: 0.5 parts of pentamethyldiethylenetriamine; 1.2 parts of dimethylcyclohexylamine; 0.5 parts of 1,3,5-tris(dimethylaminopropyl)-hexahydrotriazine;

Silicon surfactant: Niax L-6891, 2.5 parts;

Water: 1.2 parts;

Cyclopentane: 12 parts;

Component B: The material liquid temperature is 15℃,

Isobutane: 5 parts;

Polyphthalic anhydride glycol ester polyol modified isocyanate: NCO% is 23%, 173 parts;

Mold temperature is 40℃, demolding time is 4 minutes.

Example 2

Component A: The material liquid temperature is 30℃,

Compound polyol: hydroxyl value is 480mgKOH/g, 100 parts, including:

Polyether polyol A: vegetable oil-based polyol, with a hydroxyl value of 460～580mgKOH/g, 40 parts;

Polyether polyol B: polycarbonate polyol, with a hydroxyl value of 360～440mgKOH/g, 10 parts;

Polyether polyol C: phenylenediamine polyether polyol, the hydroxyl value is 480～530mgKOH/g, 20 parts;

Polyether polyol D: sorbitol, glycerin composite polyether polyol, hydroxyl value 330～420mgKOH/g, 30 parts;

Amine catalyst: 0.3 parts of bis(dimethylaminoethyl) ether, 0.7 parts of triethylenediamine, 0.5 parts of 2-hydroxypropyl trimethyl formate ammonium salt;

Silicon surfactant: 1.0 part of Niax L-6988, 0.5 part of Niax L-6863;

Water: 1.8 parts;

Cyclopentane: 15 parts;

Component B: The material liquid temperature is 10℃

N-butane: 3 parts;

Glycerol polyether polyol modified isocyanate: NCO% is 28%, 171 parts.

Mold temperature is 35°C, demolding time is 10 minutes.

Example 3

Component A: The material liquid temperature is 41℃,

Polyol composition: hydroxyl value of 550mgKOH/g, 100 parts, including:

Polyether polyol A: sucrose polyether polyol, the hydroxyl value is 500～620mgKOH/g, 50 parts;

Polyether polyol B: vegetable oil-based polyol, the hydroxyl value is 530～600mgKOH/g, 20 parts;

Polyether polyol C: xylitol, glycerin composite polyether polyol, hydroxyl value 420～560mgKOH/g, 30 parts;

Amine catalyst: 0.1 parts of bis(dimethylaminoethyl) ether, 1.4 parts of dimethylbenzylamine, 0.4 parts of dimethylethanolamine, 0.9 parts of 2,4,6-tris(dimethylaminomethyl)phenol;

Silicone surfactant: AK8830, 1.0 part;

Water: 2.5 parts;

Cyclopentane: 5 parts;

Component B: The material liquid temperature is 20℃,

N-butane: 5 parts, isobutane: 5 parts;

Polyethylene phthalate polyol modified isocyanate: NCO% is 25%, 220 parts.

Mold temperature is 45°C, demolding time is 5 minutes.

Example 4

Component A: The material liquid temperature is 25℃,

Compound polyol: hydroxyl value of 340mgKOH/g, 100 parts, including:

Polyether polyol A: Xylitol, propylene glycol composite polyether polyol, with a hydroxyl value of 360～440mgKOH/g, 50 parts;

Polyether polyol B: trimethylolpropane polyol, the hydroxyl value is 280～340mgKOH/g, 20 parts;

Polyether polyol C: polycarbonate polyol with a hydroxyl value of 390～450mgKOH/g, 30 parts;

Amine catalyst: 2.0 parts of dimethylbenzylamine, 1.1 parts of N-methyldicyclohexylamine, 0.4 parts of 1,3,5-tris(dimethylaminopropyl)-hexahydrotriazine;

Silicone surfactant: 3.0 parts AK8818, 1.0 parts AK8863;

Water: 2.2 parts;

Cyclopentane: 11 parts;

Component B: The material liquid temperature is 13℃,

Isobutane: 1 part;

Polypropylene carbonate glycol modified isocyanate: NCO% is 19%, 208 parts.

Mold temperature is 38°C, demolding time is 6 minutes.

Example 5

Component A: The material liquid temperature is 33℃,

Compound polyol: hydroxyl value of 250mgKOH/g, 100 parts, including:

Polyester polyol A: phthalic anhydride polyester polyol, with a hydroxyl value of 220～300mgKOH/g, 90 parts;

Polyester polyol B: polyethylene adipate, hydroxyl value 280～350mgKOH/g, 10 parts;

Amine catalyst: 0.4 parts of pentamethyldiethylenetriamine, 1.2 parts of N-methylimidazole, 1.4 parts of N-methyldicyclohexylamine, 2,4,6-tris(dimethylaminomethyl)phenol 1.0 parts, 2.0 parts of triethanolamine;

Silicone surfactant: 3.0 parts AK8818, 1.0 part AK8805, 1.0 part Niax L-6884;

Water: 1.5 parts;

Cyclopentane: 10 parts;

Component B: The material liquid temperature is 5℃,

N-butane: 2 parts, isobutane: 6 parts;

Polyethylene phthalate modified isocyanate: NCO% is 16%, 170 parts.

Mold temperature is 48℃, demolding time is 4 minutes.

Example 6

Component A: The material and liquid temperature is 38℃,

Compound polyol: hydroxyl value is 420mgKOH/g, 100 parts, including:

Polyether polyol A: sucrose, glycerin, ethylene glycol composite polyether polyol, hydroxyl value 480～540mgKOH/g, 60 parts;

Polyether polyol B: pentaerythritol and ethylenediamine composite polyether polyol, the hydroxyl value is 360～430mgKOH/g, 40 parts;

Amine catalyst: 0.2 parts of pentamethyldiethylenetriamine, 0.3 parts of triethylenediamine, 1.7 parts of 1,2-dimethylimidazole, 2,4,6-tris(dimethylaminomethyl)phenol 1.0 part, 1.5 parts of triethanolamine;

Silicone surfactant: 2.0 parts Niax L-6884, 1.6 parts AK8830;

Water: 0.8 parts;

Cyclopentane: 8 parts;

Component B: The material liquid temperature is 13℃,

N-butane: 5 parts, isobutane: 3 parts;

Polypropylene carbonate glycol modified isocyanate: NCO% is 31%, 120 parts.

Mold temperature is 50°C, demolding time is 4 minutes.

Example 7

Component A: The material and liquid temperature is 40℃,

Compound polyol: Hydroxyl value is 380mgKOH/g, 100 parts, including:

Polyether polyol A: sorbitol, glycerin composite polyether polyol, hydroxyl value 380～440mgKOH/g, 40 parts;

Polyether polyol B: glycerin and propylene glycol composite polyether polyol, with a hydroxyl value of 280～360mgKOH/g, 40 parts;

Vegetable oil-based polyol: the hydroxyl value is 420～480mgKOH/g, 20 parts;

Amine catalyst: 0.6 parts of pentamethyldiethylenetriamine, 2.0 parts of dimethylcyclohexylamine, 0.6 parts of 2-hydroxypropyltrimethyl formate ammonium salt;

Silicone surfactant: 1.5 parts AK8863, 1.5 parts AK8818;

Water: 1.4 parts;

Cyclopentane: 12 parts;

Component B: The material liquid temperature is 18℃,

N-butane: 3 parts, isobutane: 4 parts;

Sucrose, glycerin polyether polyol modified isocyanate: NCO% is 20%, 180 parts.

Mold temperature is 46℃, demolding time is 5 minutes.

Example 8

Component A: The material liquid temperature is 33℃,

Compound polyol: hydroxyl value of 390mgKOH/g, 100 parts, including:

Polyether polyol A: sucrose, sorbitol composite polyether polyol, hydroxyl value 420～480mgKOH/g, 50 parts;

Polyether polyol B: glycerin and propylene glycol composite polyether polyol, with a hydroxyl value of 280～360mgKOH/g, 30 parts;

Phthalic anhydride polyester polyol: the hydroxyl value is 220～300mgKOH/g, 20 parts;

Amine catalyst: 0.6 parts of pentamethyldiethylenetriamine, 1.6 parts of dimethylbenzylamine, 0.4 parts of 1,3,5-tris(dimethylaminopropyl)-hexahydrotriazine, 1.2 parts of dimethylethanolamine Copies

Silicone surfactant: 1.5 parts AK8805, 1.2 parts Niax L-6863;

Water: 1.5 parts;

Cyclopentane: 8 parts;

Component B: The material liquid temperature is 8℃,

N-butane: 5 parts, isobutane: 4 parts;

Sucrose, ethylene glycol polyether polyol modified isocyanate: NCO% is 23%, 165 parts.

The mold temperature is 44°C, and the demolding time is 6 minutes.

Example 9

Component A: The material and liquid temperature is 35°C,

Compound polyol: hydroxyl value is 400mgKOH/g, 100 parts, including:

Polyether polyol A: vegetable oil-based polyol with a hydroxyl value of 420～520mgKOH/g, 40 parts;

Polyether polyol B: polypropylene carbonate diol, hydroxyl value 360～440mgKOH/g, 10 parts;

Polyether polyol C: phenylenediamine polyether polyol, with a hydroxyl value of 380～450mgKOH/g, 20 parts;

Amine catalyst: 0.5 parts of tetramethylhexamethylene diamine, 0.2 parts of bis(dimethylaminoethyl) ether, 2.1 parts of N-methyldicyclohexylamine, 0.7 parts of 2-hydroxypropyl trimethyl formate ammonium salt;

Silicon surfactant: 1.5 parts of Niax L-6988, 1.0 part of Niax L-6863;

Water: 1.8 parts;

Cyclopentane: 10 parts;

Component B: The material liquid temperature is 12℃

N-butane: 4 parts, isobutane: 2 parts;

Adipic acid glycol polyester polyol modified isocyanate: 25%, 162 parts.

The mold temperature is 40°C, and the demolding time is 6 minutes.

Example 10

Component A: The material and liquid temperature is 35°C,

Compound polyol: hydroxyl value is 420mgKOH/g, 100 parts, including:

Amine catalyst: 0.5 part of pentamethyldiethylenetriamine, 1.6 part of dimethylcyclohexylamine, 1.0 part of 2,4,6-tris(dimethylaminomethyl)phenol, 0.6 part of triethanolamine;

Silicon surfactant: 1.5 parts of Niax L-6884, 1.5 parts of AK8830;

Water: 2 parts;

Cyclopentane: 9 parts;

Component B: The material liquid temperature is 10℃,

N-butane: 3 parts, isobutane: 3 parts;

Trimethylolpropane polyether polyol modified isocyanate: PM2010, 28%, 153 parts.

Mold temperature is 38°C, demolding time is 8 minutes.

Comparative example 1 and comparative example 3:

Part of the data of Comparative Example 1 and Comparative Example 3 are the same, described below, and the different data are described in Table 2.

Component A: The material liquid temperature is 25℃,

Compound polyol: hydroxyl value is 400mgKOH/g, 100 parts, including:

Silicon surfactant: 1.5 parts of Niax L-6988, 1.0 part of Niax L-6863;

Water: 1.8 parts;

Cyclopentane: 8 parts;

N-butane: 3 parts, isobutane: 2 parts;

Component B: The material liquid temperature is 25℃

Polyphenyl polymethylene polyisocyanate: PAPI135, 31%, 120 parts.

The mold temperature is 40°C, and the demolding time is 6 minutes.

Comparative Example 2 and Comparative Example 4:

Part of the data of Comparative Example 2 and Comparative Example 4 are the same, described below, and the different data are described in Table 2.

Component A: The material liquid temperature is 23℃,

Compound polyol: hydroxyl value is 420mgKOH/g, 100 parts, including:

Silicon surfactant: 1.5 parts of Niax L-6884, 1.5 parts of AK8830;

Water: 2 parts;

Cyclopentane: 14 parts;

Component B: The material liquid temperature is 23℃,

Polyphenyl polymethylene polyisocyanate polyisocyanate: PM2010, 32%, 128 parts.

Mold temperature is 38°C, demolding time is 8 minutes.

The relevant data of the foregoing examples and comparative examples are shown in Table 1 and Table 2, respectively. Table 1 is the raw material ratio and product performance table of Examples 1-6, and Table 2 is Example 7-10 and Comparative Example 1- 4 The raw material ratio and product performance table.

Table 1 Raw material ratio and product performance

Table 2 Raw material ratio and product performance

It can be seen from Table 1 and Table 2 that the surface pores of the rigid polyurethane foam prepared by the present invention are better than those of Comparative Examples 1 to 4, and the high and low temperature dimensional deformation rate is significantly reduced, and the foam dimensional stability is significantly improved. Compared with Examples 7 to 10 and Comparative Examples 1 to 2, under the same overfill coefficient (15%), the overall density of the foam prepared by the technical solution of the present invention is lower, but the thermal conductivity is significantly lower than that of Comparative Examples 1 to 4. The compressive strength is equivalent to that of the foam with 20% overfill coefficient of Comparative Examples 3 to 4, and the foam application performance is obviously improved. Therefore, under the same performance parameters, the technical solution of the present invention can effectively reduce the amount of material poured, reduce the foam density, and thereby reduce the production cost.

Claims

A low-density rigid polyurethane foam, which is prepared by mixing component A and component B uniformly in advance, then mixing component A and component B, mechanically mixing uniformly, and foaming; wherein, parts by weight meter,

Component A includes:

(1) Compound polyol, 100 parts, hydroxyl value 250～550mg KOH/g;

(2) Cyclopentane, 5-15 parts;

(3) Amine catalyst, 1.5-6 parts;

(4) Silicone surfactant, 1-5 parts;

(5) Water, 0.8～2.5 parts;

Combination B includes:

(1) Butane, 1-10 parts;

(2) Isocyanate, 120～220 parts;

All the above raw materials are based on 100 parts of composite polyol.
The low-density rigid polyurethane foam according to claim 1, wherein:

In the component A, the composite polyol is at least one of polyether polyol, polyester polyol, vegetable oil-based polyol or polycarbonate polyol. By weight, 100 parts of composite polyol include: 0-100 parts of ether polyols with a hydroxyl value of 120-600mg KOH/g, 0-100 parts of polyester polyols with a hydroxyl value of 100-450 mg KOH/g, and 0-40 parts of vegetable oil-based polyols with a hydroxyl value of 350 ~650mg KOH/g, 0-20 parts of polycarbonate polyol and a hydroxyl value of 30-450mg KOH/g.
The low-density rigid polyurethane foam of claim 2, wherein the polyether polyol is formed by the reaction of an active hydrogen initiator and an alkylene oxide, wherein the alkylene oxide is selected from propylene oxide, ethylene oxide or At least one of butylene oxide.
The low-density rigid polyurethane foam according to claim 1, wherein in said component B, butane is n-butane or isobutane, or a mixture of n-butane and isobutane in any ratio .
The low-density rigid polyurethane foam of claim 1, wherein the amine catalyst in the component A is selected from the group consisting of pentamethyldiethylenetriamine, dimethylbenzylamine, and dimethyl ring Hexylamine, N-methyldicyclohexylamine, triethylenediamine, tetramethylethylenediamine, tetramethylhexamethylenediamine, N-methylmorpholine, 1,2-dimethylimidazole, bis( Dimethylaminoethyl)ether, dimethylethanolamine, triethanolamine, 1,3,5-tris(dimethylaminopropyl)-hexahydrotriazine, 2,4,6-tris(dimethylaminomethyl) ) A mixture of any two or more of phenol and 2-hydroxypropyltrimethyl formate ammonium salt.
The low-density rigid polyurethane foam of claim 1, wherein the mass fraction of the isocyanate group (NCO) of the isocyanate in the component B is 16.0% to 31.0%.
The low-density rigid polyurethane foam of claim 1 or 6, wherein the isocyanate is a modified isocyanate obtained by a prepolymerization reaction of an isocyanate reactant and an isocyanate, wherein the functional The degree is 2 to 3, and the isocyanate reactant is selected from at least one of polycarbonate polyol, polyester polyol, or polyether polyol.
The low-density rigid polyurethane foam according to claim 7, wherein the polycarbonate polyol is selected from polycarbonate polyols having a hydroxyl value of 30 to 400 mg KOH/g, and the polyether polyol is selected from A polyether polyol with a hydroxyl value of 200-500 mg KOH/g, and the polyester polyol is selected from polyester polyols with a hydroxyl value of 150-400 mg KOH/g.
The low-density rigid polyurethane foam according to claim 2 or 7, characterized in that:

The polycarbonate polyol is formed by the reaction of carbon dioxide and alkylene oxide, wherein the alkylene oxide is selected from at least one of propylene oxide, ethylene oxide or butylene oxide.
The preparation method of low-density rigid polyurethane foam according to claim 1, characterized in that it comprises the following steps:

(1) Preparation of component A: add the composite polyol, cyclopentane, amine catalyst, silicon surfactant and water into the mixing kettle according to the set ratio, stir evenly to obtain component A, and control the material temperature to 25~ 41℃;

(2) Prepare component B: deliver butane and isocyanate to the mixer according to the set ratio, mix evenly to obtain component B, and control the material temperature to 5-20°C;

(3) Mixed injection: Mix component A and component B into a closed mold through a high-pressure machine gun head, and fully react. The mold temperature is controlled at 35～50℃, and the foaming material is overfilled in the mold with a coefficient of 105%～135. %, low-density rigid polyurethane foam can be obtained after demolding.