Polyurethane flexible foam material as well as preparation method and application thereof

Abstract

The invention discloses a polyurethane flexible foam material as well as a preparation method and application thereof, the raw materials of the material comprise a component A and a component B. The component A comprises the following raw materials: polyether polyol, polymer polyol, a chain extender, a foam stabilizer, a foaming catalyst and a foaming agent; the component B is prepared from the following component raw materials: MDI (methylene diphenyl diisocyanate), CO2-based polyether polyol and a polymerization inhibitor. The environment-friendly CO2-based polyether polyol is used for replacing polyether polyol or polyester polyol to modify isocyanate, so that the polyurethane flexible foam material with better stretching and tearing properties is obtained, and the polyurethane flexible foam material has higher rebound resilience and supporting property, good processability and comfortable hand feeling, and can be applied to shoe materials, automobile seat sponges and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethane, and in particular to a polyurethane soft foam material and a preparation method and application thereof. Background Art

[0002] Polyurethane is a polymer synthetic material with properties between those of rubber and plastic. It is characterized by a wide range of hardness adjustment, the elasticity of rubber and the hardness of plastic, good mechanical properties, wear resistance and resilience, and has become the fastest-growing polymer material after PE, PP, PVC, PS and phenolic resin.

[0003] At present, polyurethane soft foams are all two-component systems, namely component A and component B. Component A is a mixture of polyester polyol, foaming agent, foam leveling agent, chain extender, foaming catalyst, etc., namely the polyol component, which provides the hydroxyl groups required for the reaction; component B is a mixture obtained by reacting polyether polyol or polyester polyol with MDI (diphenylmethane diisocyanate), namely the MDI prepolymer component, which provides the isocyanate groups required for the reaction. Existing polyurethane soft foams are prone to problems such as poor tensile properties and easy tearing, which greatly affects the product qualification rate and production efficiency. Summary of the invention

[0004] Purpose of the invention: The first purpose of the present invention is to provide a polyurethane soft foam material with good tensile properties and tearing properties; the second purpose of the present invention is to provide a method for preparing the polyurethane soft foam material; the third purpose of the present invention is to provide an application of the polyurethane soft foam material.

[0005] The polyurethane soft foam material of the present invention comprises raw materials including component A and component B, wherein the component A comprises the following raw materials: polyether polyol, polymer polyol, chain extender, foam leveler, foaming catalyst and foaming agent; and the component B comprises the following raw materials: MDI, CO2-based polyether polyol and inhibitor.

[0006] Because the molecular chain of CO2-based polyether polyol contains both polyether groups and carbonate groups. The polyether group will give the polyol good fluidity and flexibility, thereby improving the elasticity of the material; while the carbonate group not only provides a higher modulus, but also further enhances the elasticity and mechanical properties of the material by forming a hydrogen bond structure. This block structure allows the material to have excellent toughness and elasticity while maintaining a certain strength. Therefore, the introduction of CO2-based polyether polyol can greatly improve the tensile and tearing properties of polyurethane soft foam.

[0007] Preferably, the polyether polyol is a mixture of one or more of the following with a hydroxyl value ranging from 20 to 50 mg KOH / g and a functionality of 3. Too high a functionality and a hydroxyl value will result in a foam with too high a hardness and poor miscibility with the MDI component. The trifunctional polyether polyol can improve the support and resilience of the soft foam, thereby avoiding the collapse of the foam.

[0008] Preferably, the polymer polyol has a hydroxyl value of 19 to 30 mgKOH / g and a solid content of 41% to 49%. The polymer polyol can increase the open cell rate and thus improve the closed cell and shrinkage of the foam.

[0009] The chain extender is ethylene glycol.

[0010] The silicone oil is one or more of Dabco DC193, L-580, and Evonik 8734.

[0011] Preferably, the foaming catalyst is A33.

[0012] The cross-linking agent is one or more of alcoholamine compounds such as triethanolamine and diethanolamine.

[0013] The foaming agent is water.

[0014] Preferably, the mass fractions of the raw materials of component B are as follows: 85-95 parts of MDI, 5-15 parts of CO2-based polyether polyol, 0.003-0.01 parts of inhibitor, and the mass percentage of isocyanate (NCO) in component B is 25%-32%.

[0015] Preferably, the CO2-based polyether polyol has a number average molecular weight of 2000-3000, a functionality of 2-3, and a CO2 content of 14%-16%. The performance of the foam will increase with the increase of the molecular weight, but too high a molecular weight will lead to poor solubility; the CO2 content should also be appropriate. The physical properties of polyether polyols with too low a CO2 content will not be significantly improved, and polyether polyols with too high a CO2 content will have a high viscosity, which is not easy to disperse in MDI and is prone to violent polymerization during the reaction.

[0016] Preferably, the MDI is one or more of MDI-100, MDI-50, liquefied MDI and polymerized MDI.

[0017] Preferably, the polymerization inhibitor is benzoyl chloride or phosphoric acid.

[0018] The method for preparing the polyurethane soft foam material of the present invention is characterized by comprising the following steps:

[0019] Step 1: Preparation of Component A

[0020] The polyether polyol and the polymer polyol are heated and stirred for vacuum dehydration, and then cooled, and then a chain extender, a foaming agent, a foaming catalyst and a foaming agent are added for blending and stirring, and the mixture is discharged after being evenly mixed to form component A;

[0021] Step 2: Preparation of component B

[0022] (1) heating the CO2-based polyether polyol and performing vacuum stirring dehydration, and cooling the polyether after measuring that the water content is less than 0.05% for standby use;

[0023] (2) adding MDI and the polymerization inhibitor to a reaction kettle and mixing them evenly, and controlling the temperature of the reaction kettle to be 50-60° C.; adding the CO2-based polyether polyol treated in step (1) to the reaction kettle, and controlling the temperature of the reaction kettle to be 77-83° C., and maintaining the reaction for 2-4 hours; cooling the mixture to less than 60° C., discharging the mixture, and obtaining component B;

[0024] Step 3: Preparation of polyurethane soft foam material

[0025] Component A and component B are quickly mixed and injected into a mold for reaction and foaming. The mold temperature is 30 to 50° C. The molding time is 2 to 10 minutes, and then demolding is performed to obtain a polyurethane soft foam material.

[0026] Preferably, the mass proportions of the raw materials of component A are as follows: 48-52 parts of polyether polyol, 48-51 parts of polymer polyol, 4-6 parts of chain extender, 0.4-0.6 parts of silicone oil, 0.5-0.7 parts of foaming catalyst, 0.9-1.1 parts of cross-linking agent, and 1.6-1.8 parts of foaming agent, and the ratio of component A to component B is 100:48-60.

[0027] Preferably, in step 1, the cooling temperature is below 40°C.

[0028] The polyurethane soft foam material of the present invention is used in shoe materials or automobile seat sponges.

[0029] Beneficial effects: Compared with the prior art, the present invention has the following advantages: (1) Component B uses environmentally friendly CO2-based polyether polyol to replace polyether polyol or polyester polyol to modify isocyanate, thereby obtaining a polyurethane soft foam material with better tensile and tearing properties; (2) The polyurethane soft foam material has low odor; (3) The polyurethane soft foam material has high resilience, support, good processing performance and comfortable hand feel, and can be used in shoe materials, car seat sponges, etc.; (4) The preparation method is simple and easy to industrialize. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with specific embodiments.

[0031] Table 1 is a list of raw materials required for the specific implementation.

[0032] Table 1 List of raw materials

[0033]

[0034] Example 1

[0035] The preparation method of the polyurethane soft foam material of the present invention comprises the following steps:

[0036] Step 1: Preparation of Component A

[0037] By weight, 50 parts of polyether polyol CHE-2801L and 50 parts of polymer polyol CHP-H45 were heated to 110° C. and stirred for vacuum dehydration for 2 hours, then cooled to 26° C., and then 5 parts of chain extender EG, 0.4 parts of silicone oil B8734, 0.1 parts of silicone oil L-580, 1 part of crosslinking agent diethanolamine DEOA, 0.6 parts of foaming catalyst A33 and 1.75 parts of water were added for blending and stirring, and the mixture was discharged after being mixed evenly to form component A.

[0038] Step 2: Preparation of component B

[0039] (1) 4 parts of CO2-based polyether polyol PCE-3015E and 3 parts of PCE-2015E were heated to 110°C and vacuum stirred for dehydration for 2 hours. After the water content of the polyether was less than 0.05%, the temperature was lowered to 50°C for standby use;

[0040] (2) By weight, 28 parts of MDI-100, 19 parts of MIPS, 21 parts of LL and 0.006 parts of benzoyl chloride were added into a reaction kettle and mixed and stirred evenly, and the temperature of the reaction kettle was controlled to be 50-60° C.; the CO2-based polyether polyol dehydrated in step (1) was added into the reaction kettle, and the temperature of the reaction kettle was controlled to be 77-83° C., and the reaction was maintained for 2 hours; heating was stopped, 25 parts of MDI M20S at room temperature were added, and stirred for 15 minutes, and the temperature was lowered to below 60° C., and the material was discharged to obtain component B, and NCO (29.4±0.3%) was measured.

[0041] Step 3: Preparation of polyurethane elastomer material:

[0042] Component A and component B are quickly mixed at a mass ratio of 100:51, injected into a mold for reaction and foaming, the mold temperature is 30-50° C., the molding time is 5 minutes, and then demolding is performed to obtain a polyurethane soft foam material.

[0043] The preparation methods of Examples 2 to 4 and Comparative Examples 1 to 3 are the same as those of Example 1. The specific components and raw material portions are shown in Table 2.

[0044] Table 2 Components and raw materials of Examples 1 to 4 and Comparative Examples 1 to 3

[0045]

[0046]

[0047] The performance of the samples prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were tested.

[0048] Inspiration time; timer;

[0049] Foam resilience performance: GB / T 6670-2008;

[0050] Tensile strength: GB / T 6344-2008;

[0051] Elongation at break: GB / T 6344-2008;

[0052] Tear strength: DBL 5450:2015;

[0053] Foam compression set -50%: GB / T 6669-2008;

[0054] Odor grade: GB / T 10802-2006.

[0055] The test results are shown in Table 3.

[0056] Table 3 Test results of physical properties of Examples 1 to 4 and Comparative Examples 1 to 3

[0057]

[0058]

[0059] It can be seen from Table 3 that the polyurethane soft foam materials prepared in Examples 1 to 4 generally have faster reactivity and faster post-maturation, which is beneficial to improving production efficiency; at the same time, the foam rebound performance, tensile strength, elongation at break, tear strength, foam compression permanent deformation and odor level are generally good.

[0060] Compared with Example 1, although Examples 5 and 6 both use CO2-based polyether polyols, their NCO contents are different and their physical properties are not as good as that of Example 1. Therefore, an NCO content of 29.4% is most preferred.

[0061] In Comparative Example 1, compared with Example 3, ordinary polyether polyol was used in component B instead of CO2-based polyether polyol, and the tensile and tear properties of the foam decreased. This is because CHE-220, as a common difunctional polyether, only has polyether groups but no carbonate groups, and therefore lacks the force of hydrogen bonds, resulting in a decrease in physical properties.

[0062] In Comparative Example 2, compared with Example 2, ordinary polyether polyol was used in component B instead of CO2-based polyether polyol, and the tensile and tear properties of the foam decreased. This is because CHE-5603, as a common trifunctional polyether, only has polyether groups but no carbonate groups, and therefore lacks the force of hydrogen bonds, resulting in a decrease in physical properties.

[0063] Comparative Example 3 Compared with Example 1, ordinary polyether polyols were used in component B instead of CO2-based polyether polyols, and the tensile and tear properties of the foam decreased, and the odor level was also high. This is because even if ordinary 2- and 3-functional polyethers are used in combination, their reaction activity is still not as fast as that of CO2-based polyether polyols. The polyurethane foam material prepared by synthesizing component B with 2- and 3-functional CO2-based polyether polyols has the best performance in all aspects.

Claims

1. A polyurethane soft foam material, characterized in that: The raw materials of the material include component A and component B. The component A includes the following raw materials: polyether polyol, polymer polyol, chain extender, foam leveler, foaming catalyst and foaming agent; the component B includes the following raw materials: MDI, CO2-based polyether polyol and inhibitor.

2. The polyurethane soft foam material according to claim 1, characterized in that: The mass proportions of the raw materials of the B component are as follows: 85-95 parts of MDI, 5-15 parts of CO2-based polyether polyol, and 0.003-0.01 parts of inhibitor. The mass percentage of isocyanate in the B component is 25%-32%.

3. The polyurethane soft foam material according to claim 1, characterized in that: The CO2-based polyether polyol has one or more of a number average molecular weight of 2000 to 3000, a functionality of 2 to 3, and a CO2 content of 14% to 16%.

4. The polyurethane soft foam material according to claim 1, characterized in that: The MDI is one or more of MDI-100, MDI-50, liquefied MDI and polymerized MDI.

5. The polyurethane soft foam material according to claim 1, characterized in that: The polyether polyol is a mixture of one or more of the three functional groups with a hydroxyl value ranging from 20 to 50 mgKOH / g.

6. The polyurethane soft foam material according to claim 1, characterized in that: The polymer polyol is one or more of the following: the polymer polyol has a hydroxyl value ranging from 19 to 30 mgKOH / g and a solid content ranging from 41% to 49%.

7. The polyurethane soft foam material according to claim 1, characterized in that: The foaming catalyst is A33.

8. A method for preparing the polyurethane soft foam material according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: Preparation of Component A The polyether polyol and the polymer polyol are heated and stirred for vacuum dehydration, and then cooled, and then a chain extender, a foaming agent, a foaming catalyst and a foaming agent are added for blending and stirring, and the mixture is discharged after being evenly mixed to form component A; Step 2: Preparation of component B (1) heating the CO2-based polyether polyol and performing vacuum stirring dehydration, and cooling the polyether after measuring that the water content is less than 0.05% for standby use; (2) adding MDI and the polymerization inhibitor to a reaction kettle and mixing them evenly, and controlling the temperature of the reaction kettle to be 50-60° C.; adding the CO2-based polyether polyol treated in step (1) to the reaction kettle, and controlling the temperature of the reaction kettle to be 77-83° C., and maintaining the reaction for 2-4 hours; cooling the mixture to less than 60° C., discharging the mixture, and obtaining component B; Step 3: Preparation of polyurethane soft foam material Component A and component B are quickly mixed and injected into a mold for reaction and foaming. The mold temperature is 30 to 50° C. The molding time is 2 to 10 minutes, and then demolding is performed to obtain a polyurethane soft foam material.

9. The polyurethane soft foam material according to claim 8, characterized in that: The mass proportions of the raw materials of component A are as follows: 48-52 parts of polyether polyol, 48-51 parts of polymer polyol, 4-6 parts of chain extender, 0.4-0.6 parts of silicone oil, 0.5-0.7 parts of foaming catalyst, 0.9-1.1 parts of cross-linking agent, and 1.6-1.8 parts of foaming agent. The ratio of component A to component B is 100:48-60.

10. Use of the polyurethane soft foam material according to any one of claims 1 to 7 in shoe materials or automobile seat sponges.

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