Preparation method of polyurethane memory foam

Abstract

This invention relates to the field of polyurethane technology, and more particularly to a method for preparing polyurethane memory foam, comprising: sampling, adding markers, and foaming; curing and cooling, continuously acquiring marker distribution images, determining the difference in the distribution of marker features between the upper and lower region images; determining the type of gravity interference during the curing and cooling process based on the distribution difference; controlling process parameters based on the type of gravity interference during the curing and cooling process; recording the mold flipping time and the determined curing time, and controlling the mold flipping time and corresponding curing time in subsequent curing and cooling processes. This invention, by adding markers during the foam preparation process and detecting the distribution of markers upon completion, analyzes the influence of gravity interference on the foam, thereby adjusting relevant parameters, reducing the impact of gravity interference on the polyurethane memory foam preparation process, and improving the uniformity of the memory foam.

Description

Technical Field

[0001] This invention relates to the field of polyurethane technology, and more particularly to a method for preparing polyurethane memory foam. Background Technology

[0002] Polyurethane memory foam possesses excellent support and pressure-relieving properties, providing a comfortable sleep experience. It can gradually deform according to body temperature and pressure, conforming to the body's curves and reducing pressure points. Existing technology prepares polyurethane memory foam using polyether polyols and polymer polyols, foam stabilizers, foaming agents, as well as polyether polyols, isocyanates, hardening agents, and polyether-based opening agents. This allows it to deform in response to temperature and pressure, exhibiting advantages such as moderate rebound speed, no closed-cell shrinkage, high physical and mechanical strength, and a certain degree of support strength. However, during the manufacturing process, when polyurethane memory foam is left to stand, gravity causes uneven deformation.

[0003] Chinese Patent Application No. CN201210305264.9 discloses a polyurethane composite material with shape memory function and its preparation and application method. This composite material consists of component A, component B, and component C. Component A comprises polyether polyol, polymer polyol, foam stabilizer, and foaming agent; component B comprises polyether polyol, isocyanate, hardening agent, and polyether-based opening agent. The resulting shape memory sponge can deform according to temperature and pressure, exhibiting advantages such as moderate rebound speed, no closed-cell shrinkage, high physical and mechanical strength, and certain support strength. Mouse pads made from this material improve the hardness and strength of traditional memory foam, providing some support for the wrist; furthermore, the unique temperature-sensitive effect and shape memory function of memory foam provide zero-pressure support to various parts of the wrist, promoting blood circulation and reducing fatigue. However, the aforementioned polyurethane composite material with shape memory function and its preparation and application method have the following problems: they do not consider the unevenness caused by gravity during the polyurethane memory foam process. Summary of the Invention

[0004] Therefore, the present invention provides a method for preparing polyurethane memory foam to overcome the problem of unevenness caused by gravity during the preparation of polyurethane memory foam in the prior art.

[0005] To achieve the above objectives, the present invention provides a method for preparing polyurethane memory foam. This method includes:

[0006] Step S1: Take samples of the raw materials required for the current batch, add markers to the samples, and inject them into the molding mold according to the predetermined process ratio for foaming and molding.

[0007] Step S2: After foaming and molding, the product is cured and cooled. During the curing and cooling process, the distribution image of the markers in the molding mold is continuously acquired. The distribution image of the markers is divided into an upper region image and a lower region image to determine the difference in the distribution of marker features between the upper region image and the lower region image.

[0008] Step S3: Determine the type of gravity interference for the aging and cooling process based on the difference in the distribution of the markers in the image after a predetermined cooling time.

[0009] Step S4: Control the process parameters of the ripening and cooling process based on the gravity interference category of the ripening and cooling process, including:

[0010] Based on the difference in distribution amount, it is determined whether the molding mold needs to be flipped. After a predetermined curing and cooling time, the gravity sedimentation rate characterization value is determined according to the change in the difference in distribution amount of marker features in the upper and lower region images, so as to optimize the predetermined curing time based on the gravity sedimentation rate characterization value.

[0011] Alternatively, maintain the reference temperature and the predetermined curing time, then complete the curing and cooling process.

[0012] Step S5: Record the mold flipping time and the determined curing time in step S4, and control the mold flipping time and corresponding curing time in the subsequent curing and cooling process of the batch.

[0013] Furthermore, in step S2, the vector corresponding to the shooting direction of the marker distribution image is perpendicular to the normal vector of the horizontal plane.

[0014] Further, determining the difference in the distribution of marker features between the upper and lower region images includes:

[0015] Determine the number of landmarks in the upper region image.

[0016] Determine the number of landmarks in the lower layer image.

[0017] The difference in the number of markers in the lower region image and the number of markers in the upper region image are used to obtain the distribution difference value.

[0018] Furthermore, the determination of the gravitational interference category for the aging and cooling process includes:

[0019] If the difference in the distribution quantity is greater than or equal to the preset standard difference in the distribution quantity, the aging and cooling process is determined to be a strong gravity interference category.

[0020] If the difference in the distribution amount is less than the preset standard difference in the distribution amount, the aging and cooling process is determined to be a weak gravity interference category.

[0021] Furthermore, the process parameters of the aging and cooling process controlled by the gravity interference category based on the aging and cooling process include:

[0022] If the curing and cooling process is of the strong gravity interference type, it is determined whether the molding mold needs to be flipped based on the difference in distribution amount. After the curing and cooling time is predetermined, the gravity sedimentation rate characterization value is determined based on the change in the difference in distribution amount of marker features in the upper region image and the lower region image, so as to optimize the predetermined curing time based on the gravity sedimentation rate.

[0023] If the curing and cooling process is of the weak gravitational interference type, the curing and cooling process is completed after maintaining the reference temperature and the predetermined curing time.

[0024] Furthermore, the step of determining whether the molding die needs to be flipped based on the difference in distribution includes:

[0025] If the difference in the distribution amount is greater than or equal to the preset difference in the distribution amount of reversal, it is determined that the molding mold should be reversed.

[0026] If the difference in the distribution amount is less than the preset difference in the distribution amount of the flipping, it is determined that the molding die will not be flipped.

[0027] The difference in the flipped distribution is determined based on the difference in the preset standard distribution.

[0028] Further, the calculation of the gravitational sedimentation rate characterization value includes:

[0029] The rate of decrease in the distribution of marker features is determined based on the upper region image;

[0030] The rate of increase in the distribution of marker features is determined based on the image of the lower region.

[0031] The difference between the rate of decrease and the rate of increase of the distribution quantity is calculated and used as a characterization value of the gravity sedimentation rate.

[0032] Further, optimizing the maturation time based on the gravity sedimentation rate characterization value includes,

[0033] The determined maturation time is positively correlated with the gravitational sedimentation rate.

[0034] Further, the upper region image and the lower region image are divided, wherein,

[0035] The upper region has the same area as the lower region.

[0036] Furthermore, under the condition that the molding die needs to be flipped, the molding die is flipped at a 180-degree angle.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows: During the preparation of polyurethane memory foam, the component mixture tends to flow downwards due to gravity. Although the component mixture is uniformly mixed, at the microscopic level, due to differences in component differences, their flow and sedimentation abilities are different, and their downward flow trends are different. This leads to uneven distribution of the prepared polyurethane memory foam, affecting the rebound effect. By adding markers during the foam preparation process and detecting the distribution of the markers after preparation, the influence of gravity interference when preparing polyurethane memory foam with the current raw materials can be analyzed based on the distribution of the markers. This allows for the adjustment of relevant parameters, reducing the influence of gravity interference on the polyurethane memory foam preparation process, improving the uniformity of the memory foam, and improving the quality of the memory foam.

[0038] In particular, although the polyurethane memory foam is molded as a mixture when it is left to stand, at the microscopic level, the heavier components tend to flow downwards more. Therefore, this invention first determines the type of gravity interference in the curing and cooling process through experiments, and then adaptively controls the process parameters of the curing and cooling process to improve the uniformity and quality of the memory foam.

[0039] In particular, this invention uses the injection of markers to characterize the flowability of the raw material mixture. In practice, the markers flow downwards, and because the detection direction is unidirectional, the markers are easily obstructed by other markers. Therefore, it is difficult to monitor the positional changes of individual markers. Thus, this invention analyzes the internal flow of polyurethane memory foam during the preparation process based on the changes in the number of markers, thereby improving the accuracy of the analysis of the degree of influence of gravity interference on polyurethane memory foam.

[0040] In particular, under the condition of strong gravitational interference during the curing and cooling process, the present invention adaptively flips the molding die based on the difference in distribution amount, so that the mixed raw materials in the molding die flow in the opposite direction, reducing the influence of gravitational interference on the curing and cooling process. Furthermore, considering the solidification process of the mixed raw materials in the molding die during the cooling process, the rate of change of the distribution amount of the upper marker features will gradually decrease during the solidification process, and the difference in the rate of change of the distribution amount between the upper and lower layers will gradually decrease. Based on this, the curing time is optimized, thereby improving the uniformity of the prepared polyurethane memory foam. Attached Figure Description

[0041] Figure 1 This is a flowchart of the preparation method of the polyurethane memory foam of the present invention;

[0042] Figure 2 This is a flowchart illustrating the determination of the gravity interference category during the aging and cooling process of this invention.

[0043] Figure 3A flowchart for determining the process parameters of the aging and cooling process in this invention;

[0044] Figure 4 This is a flowchart illustrating the process of determining whether the molding die needs to be flipped according to the present invention. Detailed Implementation

[0045] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0046] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0047] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0048] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0049] Please see Figure 1 The diagram shown is a flowchart of the preparation method of the polyurethane memory foam of the present invention.

[0050] This invention provides a method for preparing polyurethane memory foam, comprising:

[0051] Step S1: Take samples of the raw materials required for the current batch, add markers to the samples, and inject them into the molding mold according to the predetermined process ratio for foaming and molding.

[0052] Step S2: After foaming and molding, the product is cured and cooled. During the curing and cooling process, the distribution image of the markers in the molding mold is continuously acquired. The distribution image of the markers is divided into an upper region image and a lower region image to determine the difference in the distribution of marker features between the upper region image and the lower region image.

[0053] Step S3: Determine the type of gravity interference for the aging and cooling process based on the difference in the distribution of the markers in the image after a predetermined cooling time.

[0054] Step S4: Control the process parameters of the ripening and cooling process based on the gravity interference category of the ripening and cooling process, including:

[0055] Based on the difference in distribution amount, it is determined whether the molding mold needs to be flipped. After a predetermined curing and cooling time, the gravity sedimentation rate characterization value is determined according to the change in the difference in distribution amount of marker features in the upper and lower region images, so as to optimize the predetermined curing time based on the gravity sedimentation rate characterization value.

[0056] Alternatively, maintain the reference temperature and the predetermined curing time, then complete the curing and cooling process.

[0057] Step S5: Record the mold flipping time and the determined curing time in step S4, and control the mold flipping time and corresponding curing time in the subsequent curing and cooling process of the batch.

[0058] Specifically, the present invention does not specifically limit the composition of the marker, the marker does not react with the raw materials used in its preparation, and does not react in the polyurethane sponge preparation environment. For example, fluorescent dyes can be used. The number of markers can be identified by obtaining the distribution image of the markers through X-ray imaging equipment.

[0059] It is understandable that, since markers may overlap or occlude, when obtaining marker distribution images to determine the distribution quantity, multiple marker images can be repeatedly obtained to calculate the average distribution quantity in order to reduce errors. This will not be elaborated further.

[0060] Specifically, during the preparation of polyurethane memory foam, the component mixture tends to flow downwards due to gravity. Although the component mixture is uniformly mixed, at the microscopic level, due to differences in component differences, their flow and sedimentation abilities vary, resulting in different downward flow trends. This leads to uneven distribution of the prepared polyurethane memory foam, affecting its rebound effect. By adding markers during the foam preparation process and detecting their distribution upon completion, the influence of gravity interference during the preparation of polyurethane memory foam using the current raw materials can be analyzed. This allows for the adjustment of relevant parameters, reducing the impact of gravity interference on the polyurethane memory foam preparation process, improving the uniformity of the memory foam, and ultimately enhancing its quality.

[0061] Specifically, the vector corresponding to the shooting direction of the marker distribution image is perpendicular to the normal vector of the horizontal plane.

[0062] Specifically, determining the difference in the distribution of marker features between the upper and lower region images includes:

[0063] Determine the number of landmarks in the upper region image.

[0064] Determine the number of landmarks in the lower layer image.

[0065] The difference in the number of markers in the lower region image and the number of markers in the upper region image are used to obtain the distribution difference value.

[0066] Specifically, in this invention, although the polyurethane memory foam is formed from a mixture during static placement, at the microscopic level, the heavier components tend to flow downwards more. Therefore, this invention first determines the type of gravity interference during the curing and cooling process through experiments, and then adaptively controls the process parameters of the curing and cooling process to improve the uniformity and quality of the memory foam.

[0067] Specifically, this invention uses injected markers to characterize the flowability of the raw material mixture. In practice, the markers flow downwards, and because the detection direction is unidirectional, the markers are easily obstructed by other markers. Therefore, it is difficult to monitor the positional changes of individual markers. Thus, this invention analyzes the internal flow of polyurethane memory foam during the preparation process based on the changes in the number of markers, thereby improving the accuracy of the analysis of the degree of influence of gravity interference on polyurethane memory foam.

[0068] Please see Figure 2 As shown, it is a flowchart for determining the type of gravity interference in the aging and cooling process.

[0069] Specifically, the determination of the gravitational interference category for the aging and cooling process includes:

[0070] If the difference in the distribution quantity is greater than or equal to the preset standard difference in the distribution quantity, the aging and cooling process is determined to be a strong gravity interference category.

[0071] If the difference in the distribution amount is less than the preset standard difference in the distribution amount, the aging and cooling process is determined to be a weak gravity interference category.

[0072] Specifically, in this embodiment, the preset standard distribution difference is obtained by pre-measurement. The distribution difference between the number of markers in the lower region image and the number of markers in the upper region image during the preparation of different qualified polyurethane memory foams is detected and recorded. The mean of the distribution difference is calculated. The preset standard distribution difference is 0.75 to 0.85 times the mean of the distribution difference.

[0073] Please see Figure 3 As shown, it is a flowchart for determining the process parameters of the aging and cooling process.

[0074] Specifically, the process parameters for controlling the aging and cooling process based on the gravity interference category of the aging and cooling process include:

[0075] If the curing and cooling process is of the strong gravity interference type, it is determined whether the molding mold needs to be flipped based on the difference in distribution amount. After the curing and cooling time is predetermined, the gravity sedimentation rate characterization value is determined based on the change in the difference in distribution amount of marker features in the upper region image and the lower region image, so as to optimize the predetermined curing time based on the gravity sedimentation rate.

[0076] If the curing and cooling process is of the weak gravitational interference type, the curing and cooling process is completed after maintaining the reference temperature and the predetermined curing time.

[0077] Please see Figure 4 As shown, it is a flowchart for determining whether the molding die needs to be flipped.

[0078] Specifically, the step of determining whether the molding die needs to be flipped based on the difference in distribution includes:

[0079] If the difference in the distribution amount is greater than or equal to the preset difference in the distribution amount of reversal, it is determined that the molding mold should be reversed.

[0080] If the difference in the distribution amount is less than the preset difference in the distribution amount of the flipping, it is determined that the molding die will not be flipped.

[0081] The difference in the flipped distribution is determined based on the difference in the preset standard distribution.

[0082] Understandably, the purpose of setting the overturning distribution difference is to intervene in advance and avoid the influence of gravity settlement. Therefore, the overturning distribution difference is set to between 0.5 and 0.7 times the preset standard distribution difference.

[0083] Specifically, under the condition of strong gravitational interference during the curing and cooling process, the present invention adaptively flips the molding die based on the difference in distribution amount, so that the mixed raw materials in the molding die flow in the opposite direction, reducing the influence of gravitational interference on the curing and cooling process. Furthermore, considering the solidification process of the mixed raw materials in the molding die during the cooling process, the rate of change of the distribution amount of the upper marker features will gradually decrease during the solidification process, and the difference in the rate of change of the distribution amount between the upper and lower layers will gradually decrease. Based on this, the curing time is optimized, thereby improving the uniformity of the prepared polyurethane memory foam.

[0084] Specifically, calculating the gravitational sedimentation velocity characterization value includes:

[0085] The rate of decrease in the distribution of marker features is determined based on the upper region image;

[0086] The rate of increase in the distribution of marker features is determined based on the image of the lower region.

[0087] The difference between the rate of decrease and the rate of increase of the distribution quantity is calculated and used as a characterization value of the gravity sedimentation rate.

[0088] Understandably, during the cooling process, the markings in the upper layer of the mold will flow to the lower layer of the mold, and as the mixture in the mold solidifies, the flow of the markings will slow down.

[0089] Specifically, optimizing the maturation time based on the gravity sedimentation rate characterization value includes,

[0090] The determined maturation time is positively correlated with the gravitational sedimentation rate.

[0091] In this embodiment, optionally,

[0092] If the gravity sedimentation rate characterization value is greater than or equal to 1.2 times the baseline threshold value of the gravity sedimentation rate characterization value, then the maturation time is set to between 1.2 and 1.3 times the baseline maturation time.

[0093] If the gravity sedimentation rate characterization value is between 0.8 and 1.2 times the baseline threshold of the gravity sedimentation rate characterization value, then the maturation time is set as the baseline maturation time.

[0094] If the gravity sedimentation rate characterization value is less than or equal to 0.8 times the baseline threshold value of the gravity sedimentation rate characterization value, then the maturation time is set to between 0.7 and 0.8 times the baseline maturation time.

[0095] Specifically, in this embodiment, the gravity sedimentation rate characterization value benchmark threshold is obtained in advance. The gravity sedimentation rate characterization value is measured at each time node during several maturation cooling benchmark cooling times. The gravity sedimentation rate characterization values ​​after a predetermined time are recorded. The average value of the gravity sedimentation rate characterization value is calculated and set as the gravity sedimentation rate characterization value benchmark threshold. The benchmark maturation time is the initial maturation time set in the process flow. Those skilled in the art can make fine adjustments according to the actual situation.

[0096] Specifically, the upper layer image and the lower layer image are divided, wherein...

[0097] The upper and lower regions have the same area, making the upper and lower region images comparable.

[0098] Specifically, under the condition that the molding die is to be flipped, the molding die is flipped at a 180-degree angle.

[0099] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

[0100] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing polyurethane memory foam, characterized in that, include: Step S1: Take samples of the raw materials required for the current batch, add markers to the samples, and inject them into the molding mold according to the predetermined process ratio for foaming and molding. Step S2: After foaming and molding, the product is cured and cooled. During the curing and cooling process, the distribution image of the markers in the molding mold is continuously acquired. The distribution image of the markers is divided into an upper region image and a lower region image to determine the difference in the distribution of marker features between the upper region image and the lower region image. Step S3: Determine the type of gravity interference for the aging and cooling process based on the difference in the distribution of the markers in the image after a predetermined cooling time. Step S4: Control the process parameters of the ripening and cooling process based on the gravity interference category of the ripening and cooling process, including: Based on the difference in distribution amount, it is determined whether the molding mold needs to be flipped. After a predetermined curing and cooling time, the gravity sedimentation rate characterization value is determined according to the change in the difference in distribution amount of marker features in the upper and lower region images, so as to optimize the predetermined curing time based on the gravity sedimentation rate characterization value. Alternatively, maintain the reference temperature and the predetermined curing time, then complete the curing and cooling process. Step S5: Record the mold flipping time and the determined curing time in step S4, and control the mold flipping time and corresponding curing time in the subsequent curing and cooling process of the batch.

2. The method for preparing polyurethane memory foam according to claim 1, characterized in that, In step S2, the vector corresponding to the shooting direction of the marker distribution image is perpendicular to the normal vector of the horizontal plane.

3. The method for preparing polyurethane memory foam according to claim 1, characterized in that, Determining the difference in the distribution of marker features between the upper and lower layer images includes: Determine the number of landmarks in the upper region image. Determine the number of landmarks in the lower layer image. The difference in the number of markers in the lower region image and the number of markers in the upper region image are used to obtain the distribution difference value.

4. The method for preparing polyurethane memory foam according to claim 1, characterized in that, The determination of the gravitational interference category for the aging and cooling process includes: If the difference in the distribution quantity is greater than or equal to the preset standard difference in the distribution quantity, the aging and cooling process is determined to be a strong gravity interference category. If the difference in the distribution amount is less than the preset standard difference in the distribution amount, the aging and cooling process is determined to be a weak gravity interference category.

5. The method for preparing polyurethane memory foam according to claim 1, characterized in that, The process parameters for controlling the aging and cooling process based on the gravity interference category of the aging and cooling process include: If the curing and cooling process is of the strong gravity interference type, it is determined whether the molding mold needs to be flipped based on the difference in distribution amount. After the curing and cooling time is predetermined, the gravity sedimentation rate characterization value is determined based on the change in the difference in distribution amount of marker features in the upper region image and the lower region image, so as to optimize the predetermined curing time based on the gravity sedimentation rate. If the curing and cooling process is of the weak gravitational interference type, the curing and cooling process is completed after maintaining the reference temperature and the predetermined curing time.

6. The method for preparing polyurethane memory foam according to claim 4, characterized in that, The step of determining whether the molding die needs to be flipped based on the difference in distribution includes: If the difference in the distribution amount is greater than or equal to the preset difference in the distribution amount of reversal, it is determined that the molding mold should be reversed. If the difference in the distribution amount is less than the preset difference in the distribution amount of the flipping, it is determined that the molding die will not be flipped. The difference in the flipped distribution is determined based on the difference in the preset standard distribution.

7. The method for preparing polyurethane memory foam according to claim 1, characterized in that, The calculation of the gravity sedimentation rate characterization value includes: The rate of decrease in the distribution of marker features is determined based on the upper region image; The rate of increase in the distribution of marker features is determined based on the image of the lower region. The difference between the rate of decrease and the rate of increase of the distribution quantity is calculated and used as a characterization value of the gravity sedimentation rate.

8. The method for preparing polyurethane memory foam according to claim 1, characterized in that, The maturation time is optimized based on the gravity sedimentation rate characterization value. include, The determined maturation time is positively correlated with the gravitational sedimentation rate.

9. The method for preparing polyurethane memory foam according to claim 1, characterized in that, Divide the upper region image and the lower region image, wherein, The upper region has the same area as the lower region.

10. The method for preparing polyurethane memory foam according to claim 6, characterized in that, Under the condition that the molding die needs to be flipped, the molding die is flipped at a 180-degree angle.

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