Preparation method of polyurethane memory sponge

Abstract

The invention relates to the technical field of polyurethane, in particular to a preparation method of polyurethane memory sponge, which comprises the following steps: sampling, adding a marker, and carrying out foam molding, curing and cooling, continuously acquiring marker distribution images, and determining a distribution quantity difference value of marker features in the upper-layer region image and the lower-layer region image; determining a gravity interference type for the curing cooling process based on the distribution quantity difference value; process parameters are controlled based on the gravity interference type of the curing cooling process; according to the method, the markers are added in the sponge preparation process, the distribution condition of the markers is detected after preparation is completed, and the influence condition of gravity interference on the sponge is analyzed; therefore, relevant parameters are adjusted, the influence of gravity interference on the preparation process of the polyurethane memory sponge is reduced, and the uniformity of the memory sponge is improved.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane, and in particular to a method for preparing polyurethane memory foam. Background Art

[0002] Polyurethane memory foam has good support and pressure relief properties, and can provide a comfortable experience for sleeping. It can slowly deform according to body temperature and pressure, so as to fit the body curve and reduce pressure points. The existing technology uses polyether polyols and polymer polyols, foam stabilizers, foaming agents, as well as polyether polyols, isocyanates, hardeners and polyether pore opening agents to prepare polyurethane memory foam, which can produce memory deformation with temperature and pressure, and has the advantages of moderate rebound speed, no closed-cell shrinkage, high physical and mechanical strength, and certain support strength. However, when the polyurethane memory foam is left to stand during the preparation process, the polyurethane memory foam is uneven up and down due to the effect of gravity.

[0003] Chinese patent application number: CN201210305264.9 discloses a polyurethane composite material with shape memory sponge and a preparation and use method thereof. The composite material is composed of component A, component B and component C, wherein component A is composed of polyether polyol and polymer polyol, foam stabilizer and foaming agent; component B is composed of polyether polyol, isocyanate, hardener and polyether pore opening agent. The obtained shape memory sponge can produce memory deformation with temperature and pressure, and has the advantages of moderate rebound speed, non-closed cell shrinkage, high physical and mechanical strength, and certain support strength. The mouse pad made of it, on the one hand, improves the hardness and strength of traditional memory sponge, and can play a certain supporting role on the wrist; on the other hand, the memory foam has a unique temperature effect and shape memory function, which can produce zero pressure support for various parts of the wrist, promote blood circulation in various parts of the wrist, and reduce fatigue. It can be seen that the polyurethane composite material with shape memory sponge and the preparation and use method thereof have the following problems: the unevenness of the upper and lower parts due to the gravity in the process of polyurethane memory sponge is not considered. Summary of the invention

[0004] To this end, the present invention provides a method for preparing a polyurethane memory foam, so as to overcome the problem that the polyurethane memory foam is not uniformly prepared due to gravity in the prior art.

[0005] To achieve the above object, the present invention provides a method for preparing a polyurethane memory foam. The method comprises:

[0006] Step S1, sampling the raw materials required for the current batch, adding markers to the sample, and injecting them into a molding mold according to a predetermined process ratio for foaming molding;

[0007] Step S2, performing ripening and cooling after the foaming molding is completed, continuously acquiring a marker distribution image of the molding mold during the ripening and cooling process, and dividing the marker distribution image into an upper region image and a lower region image to determine a distribution amount difference of marker features in the upper region image and the lower region image;

[0008] Step S3, determining the gravity interference category for the ripening and cooling process based on the distribution amount difference of the marker distribution image after the predetermined cooling time;

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

[0010] Determine whether the molding die needs to be flipped based on the distribution difference, and determine the gravity sedimentation velocity characterization value according to the change of the distribution difference of the marker features in the upper region image and the lower region image after the predetermined aging and cooling time, so as to optimize the predetermined aging time according to the gravity sedimentation velocity characterization value;

[0011] Or, the aging and cooling are completed after maintaining the reference temperature and the predetermined aging time;

[0012] Step S5, recording the mold flipping moment and the determined aging time in step S4, and controlling the mold flipping moment and the corresponding aging time in the subsequent aging 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] Furthermore, the determining of the difference in distribution amount of the marker features in the upper region image and the lower region image includes:

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

[0016] Determine the number of landmarks in the underlying region image,

[0017] The distribution amount difference is obtained by calculating the difference between the number of markers in the lower region image and the number of markers in the upper region image.

[0018] Furthermore, the determination of the gravity interference category of the ripening and cooling process includes:

[0019] If the distribution amount difference is greater than or equal to the preset standard distribution amount difference, the ripening and cooling process is determined to be a gravity strong interference type;

[0020] If the distribution amount difference is less than the preset standard distribution amount difference, it is determined that the aging and cooling process is a gravity weak interference type.

[0021] Furthermore, the gravity interference type based on the ripening and cooling process controls the process parameters of the ripening and cooling process, including:

[0022] If the aging and cooling process is a gravity strong interference category, it is determined whether the molding die needs to be turned over based on the distribution difference, and after the predetermined aging and cooling time, the gravity sedimentation velocity characterization value is determined based on the change in the distribution difference of the marker features in the upper area image and the lower area image to optimize the predetermined aging time according to the gravity sedimentation velocity;

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

[0024] Further, the determining whether the forming mold needs to be flipped based on the distribution amount difference includes:

[0025] If the distribution amount difference is greater than or equal to a preset flip distribution amount difference, it is determined that the molding die is flipped;

[0026] If the distribution amount difference is less than the preset flip distribution amount difference, it is determined that the forming mold is not flipped;

[0027] Wherein, the flip distribution amount difference is determined based on the preset standard distribution amount difference.

[0028] Further, calculating the gravity sedimentation velocity characterization value includes:

[0029] Determine the rate of decrease in the distribution of the marker feature based on the image of the upper region;

[0030] Determining the rate of increase of the distribution amount of the marker feature based on the image of the underlying region;

[0031] The difference between the rate at which the distribution amount decreases and the rate at which the distribution amount increases is calculated as the value representing the gravity sedimentation velocity.

[0032] Further, the optimizing the aging time according to the gravity sedimentation velocity characterization value includes:

[0033] The determined aging time is positively correlated with the characteristic value of gravity sedimentation velocity.

[0034] Further, the upper layer area image and the lower layer area image are divided, wherein:

[0035] The upper region is equal to the lower region in area.

[0036] Further, under the condition that it is determined that the molding die is to be flipped, the molding die is flipped at a flip angle of 180 degrees.

[0037] Compared with the prior art, the beneficial effect of the present invention lies in that, during the preparation process of the polyurethane memory foam, the component mixture tends to flow downward under the action of gravity. Although the component mixture has been evenly mixed, at the microscopic level, due to the differences in the components, their flow and sedimentation abilities are different, and their downward flow tendencies are different, which leads to uneven distribution of the prepared polyurethane memory foam, affecting the rebound effect. By adding markers during the sponge preparation process to detect the distribution of the markers when the preparation is completed, and then analyzing the influence of gravity interference when preparing the polyurethane memory foam with the current preparation raw materials according to the distribution of the markers, the relevant parameters are adjusted to reduce the influence of gravity interference on the preparation process of the polyurethane memory foam, improve the uniformity of the memory foam, and improve the quality of the memory foam.

[0038] In particular, when the polyurethane memory foam of the present invention is left to stand, although it is formed as a mixture, at the microscopic level, the heavier components tend to flow downward more. Therefore, the present invention first determines the gravity interference category of the aging and cooling process through experiments, and then adaptively controls the process parameters of the aging and cooling process, thereby improving the uniformity of the memory foam and improving the quality of the memory foam.

[0039] In particular, the present invention adopts the form of injecting markers to characterize the fluidity of the raw material mixture. In actual situations, the markers flow downward. Since the detection direction is single, the markers are easily blocked by other markers. Therefore, it is difficult to monitor the changes in the position of a single marker. Therefore, the present invention analyzes the internal flow conditions during the preparation process of the polyurethane memory foam 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 the polyurethane memory foam.

[0040] In particular, when the aging and cooling process of the present invention is in the category of strong gravity interference, the molding mold is adaptively flipped based on the distribution amount difference, so that the mixed raw materials in the molding mold flow in the opposite direction, reducing the influence of gravity interference on the aging and cooling process. In addition, considering the solidification process of the mixed raw materials in the molding mold during the cooling process, the distribution amount change rate of the upper layer marker characteristics will gradually decrease during the solidification process, and the difference in the distribution amount change rate of the upper and lower layers will gradually decrease. Based on this, the aging time is optimized, thereby improving the uniformity of the prepared polyurethane memory foam. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The present invention is a flow chart of the method for preparing the polyurethane memory foam;

[0042] Figure 2 A flow chart for determining the gravity interference category of the ripening and cooling process of the present invention;

[0043] Figure 3A flow chart for determining the process parameters of the aging and cooling process of the present invention;

[0044] Figure 4 The present invention is a flow chart for determining whether the molding die needs to be flipped. DETAILED DESCRIPTION

[0045] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0047] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0048] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] See also Figure 1 As shown, it is a flow chart of the preparation method of the polyurethane memory foam of the present invention.

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

[0051] Step S1, sampling the raw materials required for the current batch, adding markers to the sample, and injecting them into a molding mold according to a predetermined process ratio for foaming molding;

[0052] Step S2, performing ripening and cooling after the foaming molding is completed, continuously acquiring a marker distribution image of the molding mold during the ripening and cooling process, and dividing the marker distribution image into an upper region image and a lower region image to determine a distribution amount difference of marker features in the upper region image and the lower region image;

[0053] Step S3, determining the gravity interference category for the ripening and cooling process based on the distribution amount difference of the marker distribution image after the predetermined cooling time;

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

[0055] Determine whether the molding die needs to be flipped based on the distribution difference, and determine the gravity sedimentation velocity characterization value according to the change of the distribution difference of the marker features in the upper region image and the lower region image after the predetermined aging and cooling time, so as to optimize the predetermined aging time according to the gravity sedimentation velocity characterization value;

[0056] Or, the aging and cooling are completed after maintaining the reference temperature and the predetermined aging time;

[0057] Step S5, recording the mold flipping moment and the determined aging time in step S4, and controlling the mold flipping moment and the corresponding aging time in the subsequent aging 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 preparation raw materials, and does not react in the polyurethane sponge preparation environment, such as fluorescent dyes. The marker distribution image can be obtained by X-ray detection equipment to identify the number of labeled objects.

[0059] It is understandable that, since there will be a certain degree of overlap and occlusion of the labeled objects, when obtaining the marker distribution image to determine the distribution amount, multiple marker images can be repeatedly obtained to solve the mean of the distribution amount to reduce errors, which will not be elaborated here.

[0060] Specifically, during the preparation process of polyurethane memory foam, due to the action of gravity, the component mixture tends to flow downward. Although the component mixture has been evenly mixed, at the microscopic level, due to the differences in the components, their flow and sedimentation abilities are different, and the downward flow trends are different, which leads to uneven distribution of the prepared polyurethane memory foam, affecting the rebound effect. By adding markers during the sponge preparation process to detect the distribution of the markers when the preparation is completed, and then analyzing the influence of gravity interference when preparing the polyurethane memory foam with the current raw materials according to the distribution of the markers, the relevant parameters are adjusted to reduce the influence of gravity interference on the preparation process of the polyurethane memory foam, improve the uniformity of the memory foam, and improve the quality of the memory foam.

[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 distribution amount of the marker features in the upper region image and the lower region image includes:

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

[0064] Determine the number of landmarks in the underlying region image,

[0065] The distribution amount difference is obtained by calculating the difference between the number of markers in the lower region image and the number of markers in the upper region image.

[0066] Specifically, when the polyurethane memory foam of the present invention is left to stand, although the mixture is formed, at the microscopic level, the heavier components tend to flow downward more. Therefore, the present invention first determines the gravity interference category of the aging and cooling process through experiments, and then adaptively controls the process parameters of the aging and cooling process, thereby improving the uniformity of the memory foam and improving the quality of the memory foam.

[0067] Specifically, the present invention adopts the form of injecting markers to characterize the fluidity of the raw material mixture. In actual situations, the markers flow downward. Due to the single detection direction, the markers are easily blocked by other markers. It is therefore difficult to monitor the changes in the position of a single marker. Therefore, the present invention analyzes the internal flow conditions during the preparation of the polyurethane memory foam based on the changes in the number of markers, thereby improving the accuracy of the analysis of the degree to which the polyurethane memory foam is affected by gravity interference.

[0068] See also Figure 2 As shown, it is a flow chart for determining the gravity interference category of the ripening and cooling process.

[0069] Specifically, the determination is for the gravity interference category of the ripening and cooling process, including:

[0070] If the distribution amount difference is greater than or equal to the preset standard distribution amount difference, the ripening and cooling process is determined to be a gravity strong interference type;

[0071] If the distribution amount difference is less than the preset standard distribution amount difference, it is determined that the aging and cooling process is a gravity weak interference type.

[0072] Specifically, in this embodiment, the preset standard distribution amount difference is obtained in advance, and the distribution amount difference between the number of markers in the lower area image of the marker and the number of markers in the upper area image in the preparation process of different qualified polyurethane memory foams is detected and recorded, and the mean of the distribution amount difference is solved. The preset standard distribution amount difference is 0.75 to 0.85 times the mean of the distribution amount difference.

[0073] See also Figure 3 As shown, it is a flow chart for determining the process parameters of the ripening and cooling process.

[0074] Specifically, the gravity interference type based on the ripening and cooling process controls the process parameters of the ripening and cooling process, including:

[0075] If the aging and cooling process is a gravity strong interference category, it is determined whether the molding die needs to be turned over based on the distribution difference, and after the predetermined aging and cooling time, the gravity sedimentation velocity characterization value is determined based on the change in the distribution difference of the marker features in the upper area image and the lower area image to optimize the predetermined aging time according to the gravity sedimentation velocity;

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

[0077] See also Figure 4 As shown, it is a flow chart for determining whether the molding die needs to be flipped.

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

[0079] If the distribution amount difference is greater than or equal to a preset flip distribution amount difference, it is determined that the molding die is flipped;

[0080] If the distribution amount difference is less than the preset flip distribution amount difference, it is determined that the forming mold is not flipped;

[0081] Wherein, the flip distribution amount difference is determined based on the preset standard distribution amount difference.

[0082] It is understandable that the purpose of setting the flip distribution amount difference is to intervene in advance to avoid the influence of gravity sedimentation, so the flip distribution amount difference is set to between 0.5 and 0.7 times the preset standard distribution amount difference.

[0083] Specifically, when the aging and cooling process is in the category of strong gravity interference, the present invention adaptively flips the molding mold based on the distribution amount difference, so that the mixed raw materials in the molding mold flow in the opposite direction, reducing the influence of gravity interference on the aging and cooling process. In addition, considering the solidification process of the mixed raw materials in the molding mold during the cooling process, the distribution amount change rate of the upper layer marker characteristics will gradually decrease during the solidification process, and the difference in the distribution amount change rate of the upper and lower layers will gradually decrease. Based on this, the aging time is optimized, thereby improving the uniformity of the prepared polyurethane memory foam.

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

[0085] Determine the rate of decrease in the distribution of the marker feature based on the image of the upper region;

[0086] Determining the rate of increase of the distribution amount of the marker feature based on the image of the underlying region;

[0087] The difference between the rate at which the distribution amount decreases and the rate at which the distribution amount increases is calculated as the value representing the gravity sedimentation velocity.

[0088] It is understood that during the cooling process, the markers in the upper layer of the molding die will flow to the lower layer of the molding die, and as the mixture in the molding die solidifies, the flow of the markers will slow down.

[0089] Specifically, the optimizing the aging time according to the gravity sedimentation velocity characterization value includes:

[0090] The determined aging time is positively correlated with the characteristic value of gravity sedimentation velocity.

[0091] In this embodiment, optionally,

[0092] If the gravity sedimentation velocity characterization value is greater than or equal to 1.2 times the gravity sedimentation velocity characterization value reference threshold, the aging time is set to be between 1.2 times and 1.3 times the reference aging time.

[0093] If the gravity sedimentation velocity characterization value is between 0.8 and 1.2 times the gravity sedimentation velocity characterization value reference threshold value, the aging time is set as the reference aging time;

[0094] If the gravity sedimentation velocity characterization value is less than or equal to 0.8 times the gravity sedimentation velocity characterization value reference threshold, the aging time is set to be between 0.7 and 0.8 times the reference aging time.

[0095] Specifically, in this embodiment, the gravity sedimentation rate characterization value benchmark threshold is obtained in advance, and the gravity sedimentation rate characterization value at each time node in the process of several aging cooling benchmark cooling times is measured, and each gravity sedimentation rate characterization value after a predetermined time is recorded. The average value of the gravity sedimentation rate characterization value is solved and set as the gravity sedimentation rate characterization value benchmark threshold. The benchmark aging time is the initial aging time set in the process flow. Technical personnel in this field can make fine adjustments according to actual conditions.

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

[0097] The upper region and the lower region have equal areas, so that the image of the upper region is comparable to the image of the lower region.

[0098] Specifically, under the condition that it is determined that the molding die is to be reversed, the molding die is reversed at a reverse angle of 180 degrees.

[0099] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle 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 fall within the protection scope of the present invention.

[0100] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a polyurethane memory foam, characterized in that: include: Step S1, sampling the raw materials required for the current batch, adding markers to the sample, and injecting them into a molding mold according to a predetermined process ratio for foaming molding; Step S2, performing ripening and cooling after the foaming molding is completed, continuously acquiring a marker distribution image of the molding mold during the ripening and cooling process, and dividing the marker distribution image into an upper region image and a lower region image to determine a distribution amount difference of marker features in the upper region image and the lower region image; Step S3, determining the gravity interference category for the ripening and cooling process based on the distribution amount difference of the marker distribution image after the predetermined cooling time; Step S4, controlling the process parameters of the ripening and cooling process based on the gravity interference type of the ripening and cooling process, including: Determine whether the molding die needs to be flipped based on the distribution difference, and determine the gravity sedimentation velocity characterization value according to the change of the distribution difference of the marker features in the upper region image and the lower region image after the predetermined aging and cooling time, so as to optimize the predetermined aging time according to the gravity sedimentation velocity characterization value; Or, the aging and cooling are completed after maintaining the reference temperature and the predetermined aging time; Step S5, recording the mold flipping moment and the determined aging time in step S4, and controlling the mold flipping moment and the corresponding aging time in the subsequent aging and cooling process of the batch.

2. The method for preparing the 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 the polyurethane memory foam according to claim 1, characterized in that: The determining of the difference in the distribution amount of the marker features in the upper layer area image and the lower layer area image comprises: Determine the number of landmarks in the upper region image, Determine the number of landmarks in the underlying region image, The distribution amount difference is obtained by calculating the difference between the number of markers in the lower region image and the number of markers in the upper region image.

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

5. The method for preparing the polyurethane memory foam according to claim 1, characterized in that: The gravity interference type based on the ripening and cooling process controls the process parameters of the ripening and cooling process, including: If the aging and cooling process is a gravity strong interference category, it is determined whether the molding die needs to be turned over based on the distribution difference, and after the predetermined aging and cooling time, the gravity sedimentation velocity characterization value is determined based on the change in the distribution difference of the marker features in the upper area image and the lower area image to optimize the predetermined aging time according to the gravity sedimentation velocity; If the aging and cooling process is of the weak gravity interference type, the aging and cooling is completed after maintaining the reference temperature and the predetermined aging time.

6. The method for preparing the polyurethane memory foam according to claim 1, characterized in that: The determining whether the forming mold needs to be flipped based on the distribution amount difference includes: If the distribution amount difference is greater than or equal to a preset flip distribution amount difference, it is determined that the molding die is flipped; If the distribution amount difference is less than the preset flip distribution amount difference, it is determined that the forming mold is not flipped; Wherein, the flip distribution amount difference is determined based on the preset standard distribution amount difference.

7. The method for preparing the polyurethane memory foam according to claim 1, characterized in that: Calculating the gravity sedimentation velocity characterization value includes: Determine the rate of decrease in the distribution of the marker feature based on the image of the upper region; Determining the rate of increase of the distribution amount of the marker feature based on the image of the underlying region; The difference between the rate at which the distribution amount decreases and the rate at which the distribution amount increases is calculated as the value representing the gravity sedimentation velocity.

8. The method for preparing the polyurethane memory foam according to claim 1, characterized in that: said optimizing the aging time according to the gravity sedimentation velocity characterization value, include, The determined aging time is positively correlated with the characteristic value of gravity sedimentation velocity.

9. The method for preparing the polyurethane memory foam according to claim 1, characterized in that: The upper layer region image and the lower layer region image are divided, wherein: The upper region is equal to the lower region in area.

10. The method for preparing the polyurethane memory foam according to claim 6, characterized in that: Under the condition that it is determined that the molding die is to be turned over, the molding die is turned over at a turning angle of 180 degrees.

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