Hot melt adhesive filling method and filling device

Abstract

The present invention belongs to the technical field of polymer material processing, and specifically relates to a hot melt adhesive filling method and filling device. During filling, the hose is preheated to allow the hose to expand due to heat first, ensuring that the viscosity of the hot melt adhesive does not increase due to cooling during filling. The preheated hose expands due to heat, and will have a greater shrinkage rate during subsequent cooling to match the cooling and shrinkage of the hot melt adhesive, preventing the hot melt adhesive from detaching from the hose due to excessive shrinkage. Uniform cooling can reduce the volume shrinkage of the hot melt adhesive during the cooling process, further reducing the risk of the hot melt adhesive detaching from the hose; thereby improving the production yield of the hot melt adhesive, reducing production costs, and reducing transportation and storage conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer material processing, and particularly relates to a hot melt adhesive filling method and a filling device. Background Art

[0002] Traditional high initial strength hot melt adhesives increase initial adhesion by adding too many crystalline and thermoplastic components. The introduction of these components will increase the overall Tg of the hot melt adhesive, which is very likely to cause wall delamination during filling. Weakening the internal stress generated by the high Tg component when it is rapidly cooled and experiences the glass transition temperature can reduce the occurrence of wall delamination. The existing process places the filled hot melt adhesive in an insulation cavity, uses the heat release of the hot melt adhesive itself to increase the ambient temperature in the cavity, and works together with the insulation structure to reduce the cooling rate of the environment. At the same time, the insulation cavity is placed in a constant temperature box to further delay the drop in ambient temperature. This type of process has the following problems: the temperature at different positions in the insulation cavity is inconsistent, the hot melt adhesive at the center position receives heat radiation from all sides, and the edge position can only receive heat radiation from the inside to the outside. Overall, the temperature at the center position is relatively high and the temperature around it is relatively low, and the temperature decreases from the inside to the outside. The cooling rate on the outside is relatively fast and it is easy to fall off the wall; delaying the cooling of the system by heat radiation + insulation cavity + constant temperature environment takes a long time, usually 1 to 2 days, which is time-consuming and has low production efficiency; long-term heat radiation will cause aging of some heat-sensitive components of the hot melt adhesive, and accelerate the reaction of reactive components, affecting the performance of the hot melt adhesive. Summary of the Invention

[0003] In view of this, the present invention proposes a hot melt adhesive filling method and filling device. During filling, the hose is preheated to allow the hose to expand due to heat first, ensuring that the viscosity of the hot melt adhesive will not increase due to cooling during filling, and the preheated hose expands due to heat, and will have a larger shrinkage rate during subsequent cooling to match the cooling and shrinkage of the hot melt adhesive to prevent the hot melt adhesive from separating from the hose due to excessive shrinkage. Uniform cooling can reduce the volume shrinkage of the hot melt adhesive during the cooling process, further reducing the risk of the hose coming off; it improves the production yield of the hot melt adhesive, reduces production costs, and reduces transportation and storage conditions.

[0004] In order to achieve the above technical objectives, the specific technical solutions adopted by the present invention are:

[0005] A hot melt adhesive filling method comprises the following steps:

[0006] S101: Preheating a hose for filling the hot melt adhesive;

[0007] S102: Filling hot melt adhesive into the preheated hose;

[0008] S103: Temporarily keeping the hose filled with hot melt adhesive warm;

[0009] S104: Repeat S101-S103 to continue filling and keeping the next tube warm until the number of filled and kept warm reaches the target number;

[0010] S105: After the target number of hoses are filled, the hoses in temporary heat preservation are placed in a cooling device and cooled to room temperature at a uniform speed.

[0011] Furthermore, the preheating temperature of the hose is higher than the temperature of the hot melt adhesive before filling.

[0012] Furthermore, the preheating temperature of the hose is 5 to 10° C. higher than the temperature of the hot melt adhesive before filling.

[0013] Furthermore, the temperature of the hot melt adhesive before filling is 80-150°C.

[0014] Furthermore, the hose is cooled uniformly to room temperature at a rate of 10-20° C. / Hour.

[0015] Furthermore, the cooling equipment is an oven.

[0016] The present invention also provides a hot melt adhesive filling device for completing the above hot melt adhesive filling method, comprising:

[0017] Bracket;

[0018] A plurality of heating and heat-insulating sleeves are installed on the bracket and are provided with a rubber hose cavity, and a rubber inlet is provided at the bottom of the rubber hose cavity;

[0019] A filling device is used to fill the hot melt adhesive into the hose in the hose cavity based on the glue inlet.

[0020] Each of the heating and heat-insulating sleeves can be rotatably mounted on the bracket.

[0021] Furthermore, the filling device includes a glue feed channel and an opening and closing valve; a heat preservation device is provided outside the glue feed channel; and the opening and closing valve is used to open and close the glue feed channel.

[0022] Furthermore, when the hose is in the hose cavity, the distance between the side surface of the hose and the heating and insulation sleeve is 1-2 mm.

[0023] By adopting the above technical solution, the present invention can also bring the following beneficial effects:

[0024] The temperature of the hose of the present invention is slightly higher than that of the hot melt adhesive, further reducing the viscosity of the hot melt adhesive in contact with the hose and improving the fluidity of the hot melt adhesive;

[0025] The present invention adopts the technical means of batch filling and batch cooling, which can reduce production costs and save production time. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is a schematic flow chart of a hot melt adhesive filling method according to a specific embodiment of the present invention;

[0028] Figure 2 This is a schematic structural diagram of a hot melt adhesive filling device in a specific embodiment of the present invention;

[0029] Among them: 1. Glue inlet channel; 2. Opening and closing valve; 3. Heating and insulation sleeve; 4. Hose; 5. Bracket; 6. Photoelectric sensor; 7. Hose cavity. DETAILED DESCRIPTION

[0030] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0031] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present invention, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.

[0033] It should also be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. The illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0034] Additionally, in the following description, specific details are provided to provide a thorough understanding of the examples. However, one skilled in the art will appreciate that the aspects described can be practiced without these specific details.

[0035] In one embodiment of the present invention, a hot melt adhesive filling method is provided, such as Figure 1 As shown, the following steps are included:

[0036] S101: Preheating the hose 4 for filling hot melt adhesive;

[0037] S102: Filling hot melt adhesive into the preheated rubber hose 4;

[0038] S103: Temporarily keeping the hose 4 filled with hot melt adhesive warm;

[0039] S104: Repeat S101-S103 to continue filling and keeping the next tube 4 warm until the number of filled and kept warm tubes 4 reaches the target number;

[0040] S105: After the target number of hoses 4 are filled, each hose 4 in temporary heat preservation is placed in a cooling device and cooled to room temperature at a uniform speed.

[0041] In this embodiment, the preheating device utilizes a heated platen or other heating device. The temporary heat-insulating device comprises a preheating and / or heating device capable of accommodating the hoses 4, including multiple sets. After the target number of hoses 4 have been filled and held, they are placed together in a cooling device. The cooling device is a heating device capable of providing a cooling rate suitable for all hoses 4.

[0042] In this embodiment, the preheating temperature of the hose 4 is higher than the temperature of the hot melt adhesive before filling.

[0043] In this embodiment, the preheating temperature of the hose 4 is 5-10° C. higher than the temperature of the hot melt adhesive before filling.

[0044] In this embodiment, the temperature of the hot melt adhesive before filling is 80-150° C. When the hot melt adhesive is PUR hot melt adhesive, the temperature before filling is set to 80-100° C.

[0045] In this embodiment, the hose 4 is cooled uniformly to room temperature at a rate of 10-20° C. / Hour.

[0046] In this embodiment, the cooling device is an oven.

[0047] In this embodiment, the hose 4 is preheated before filling (the preheating temperature is 5-10°C higher than the heating temperature of the hot melt adhesive) to make the hose 4 expand due to the heat first. When the high-temperature hot melt adhesive (80-150°C, the temperature of the non-reactive hot melt adhesive can be controlled at 100-150°C according to the specific formula, and the PUR hot melt adhesive is controlled at 80-100°C) is injected into the hose 4 from the bottom to the top through the nozzle of the hose 4, the viscosity will not increase due to cooling, which will cause the wettability of the tube wall to deteriorate. At the same time, since the temperature of the hose 4 is slightly higher than the temperature of the hot melt adhesive, the viscosity of the hot melt adhesive in contact with the hose 4 is further reduced, the fluidity of the hot melt adhesive is increased, and the wettability of the hot melt adhesive to the tube wall of the hose 4 is improved. The filled hot melt adhesive is placed in insulation materials such as asbestos, aerogel and high-temperature resistant foam for insulation. After a batch of filling is completed, the hose 4 is transferred to a test tube rack and placed in a high-temperature (80-150°C) oven for uniform cooling (at a rate of 10-20°C / Ho). ur speed cooling, cooling to 25 ℃, PUR hot melt adhesive requires a low humidity environment), the pre-heated hose 4 can improve the wettability of the hot melt adhesive to the tube wall (hot melt adhesive has low viscosity, good fluidity and good wettability at high temperatures). More importantly, the pre-heated hose 4 expands when heated, and will have a larger shrinkage rate during subsequent cooling to match the cooling and shrinkage of the hot melt adhesive to prevent the hot melt adhesive from separating from the hose 4 due to excessive shrinkage - during the cooling process, the hose 4 will always be in close contact with the hot melt adhesive (the shrinkage caused by the cooling of the hose 4 after the thermal expansion is much greater than the shrinkage caused by the cooling of the hot melt adhesive from liquid to paste or semi-solid). Uniform cooling can reduce the volume shrinkage of the hot melt adhesive during the cooling process, further reducing the risk of tube detachment. No tube detachment occurred when stored at -10 ℃, and the cooling time was basically within 10-15 hours, which improved the production yield of the hot melt adhesive, reduced production costs, and reduced transportation and storage conditions.

[0048] In one embodiment, based on the same inventive concept, the present invention proposes a hot melt adhesive filling device for completing the above-mentioned hot melt adhesive filling method, comprising:

[0049] Bracket 5;

[0050] A plurality of heating and insulation sleeves 3 are mounted on a bracket 5 and are provided with a rubber tube cavity 7. A rubber inlet is provided at the bottom of the rubber tube cavity 7.

[0051] The filling device is used to fill hot melt adhesive into the rubber tube 4 in the rubber tube cavity 7 based on the glue inlet.

[0052] In this embodiment, each heating and heat-insulating sleeve 3 is rotatably mounted on the bracket 5 .

[0053] In this embodiment, when the rubber hose 4 is in the rubber hose cavity 7, the distance between the side surface of the rubber hose 4 and the heating and heat-insulating sleeve 3 is 1-2 mm.

[0054] In this embodiment, the filling device includes a glue feed channel 1 and an opening and closing valve 2 ; a heat preservation device is provided outside the glue feed channel 1 ; and the opening and closing valve 2 is used to open and close the glue feed channel 1 .

[0055] In one embodiment, the end of the glue feed channel 1 is threaded, and the bottom of the rubber hose 4 can be connected to the end of the glue feed channel 1 via the thread, thereby achieving hot melt adhesive filling that is isolated from the external environment. The glue feed channel of this embodiment is fixed to a position that each heating and insulation sleeve 3 can reach after rotation. After each rubber hose 4 reaches the base, it can be fixed to the base via the thread to achieve filling one by one.

[0056] In this embodiment, the thread arrangement at the end of the glue inlet channel 1 can be achieved by directly arranging the thread at the end of the glue inlet channel 1 .

[0057] Example 1: The produced non-reactive hot melt adhesive is melted by a pressure plate at 130°C and then pumped into the filling device through a pipeline. First, 1-2 kg of hot melt adhesive is used to clean the filling flow channel. After all the flow channels including the glue inlet flow channel 1 are cleaned, the hose 4 is placed in the heating and insulation sleeve 3 heated to 140°C, the glue nozzle part is tightened to the glue outlet of the pipeline, and the photoelectric sensor 6 is aligned with the specified position of the hose 4 to identify the glue filling amount of the hose 4. Glue is poured, and the hot melt adhesive liquid level is higher than the heating protection range of the heating and insulation sleeve 3. The photoelectric sensor 6 identifies the liquid level position and stops glue filling. The hose 4 is quickly taken out and the core head plug and tail plug are packaged and placed in the insulation cavity. After a batch of filling is completed, it is transferred to the test tube rack and placed in an oven heated to 130°C. The cooling rate is set to 15°C / Hour. After cooling to 25°C, it is taken out and packaged.

[0058] Example 2: The produced PUR hot melt adhesive is melted by a pressure plate at 90°C and then pumped into a filling device in a vacuum glove box through a pipe. First, 1-2 kg of hot melt adhesive is used to clean the filling flow channel. After all the flow channels including the glue inlet flow channel 1 are cleaned, the hose 4 is placed in a heating and insulation sleeve 3 heated to 110°C, the glue nozzle part is tightened to the glue outlet of the pipe, and the photoelectric sensor 6 is aligned with the specified position of the hose 4 to identify the glue filling amount of the hose 4. After glue filling, the hot melt adhesive liquid level is higher than the heating protection range of the heating and insulation sleeve 3. The photoelectric sensor 6 identifies the liquid level position and stops glue filling. The hose 4 is quickly taken out and the core head plug and tail plug are packaged and placed in the insulation cavity. After a batch of filling is completed, it is transferred to a test tube rack and placed in a vacuum drying oven heated to 90°C. The cooling rate is set to 10°C / Hour and vacuum drying is turned on. After cooling to 25°C, it is taken out and packaged.

[0059] Table 1 shows the test results of hot melt adhesive filling using the above two embodiments and other comparative examples:

[0060] Table 1

[0061]

[0062] The process differences between the embodiment and the comparative example are as follows:

[0063] The difference between Example 1 and Comparative Example 1-2 is that Comparative Example 1-2 adopts a filling process without preheating the hose 4, and only heat preservation and uniform cooling;

[0064] The difference between Example 1 and Comparative Examples 1-3 is that Comparative Examples 1-3 use a preheating hose 4 to keep the heat in the heat-insulating cavity;

[0065] The difference between Example 2 and Comparative Example 2-2 is that Comparative Example 2-2 adopts a filling process without preheating the hose 4, and only heat preservation and uniform cooling;

[0066] The difference between Example 1 and Comparative Examples 2-3 is that Comparative Examples 2-3 use a preheating hose 4 to keep the heat in the heat-insulating cavity;

[0067] The test methods used in the above examples and comparative examples are as follows:

[0068] (1) Bonding strength test

[0069] Test Method: Heat the hot melt adhesive dispenser's heating sleeve to 120°C. Place the hot melt adhesive in the sleeve and heat for 10-20 minutes until it is completely melted. Using the appropriate dispensing needle and dispensing path parameters, dispense the adhesive onto the substrate to be bonded. The adhesive is then pressed against another substrate, with the thickness controlled by a spacer (0.1mm-0.2mm). Finally, the bond strength is tested using a universal testing machine after 10 minutes.

[0070] Test results: The test results of the bonding strength test are shown in Table 1. As shown in Table 1, the initial strength of the hot melt adhesives prepared by the present invention after 10 minutes is greater than 1 MPa, which shows that the hot melt adhesives of the present invention are qualified products and are hot melt adhesives with high initial strength.

[0071] (1) Wall removal rate test

[0072] Test method: Store hot melt adhesives sealed in aluminum foil bags at 0°C for 30 days and at -10°C for 3 days. Remove the foil bags and count the number of adhesives showing debonding. Calculate the debonding rate: (number of adhesives showing debonding / total number of adhesives) x 100%.

[0073] Test results: By preheating the hose 4 and then cooling it at a uniform rate, the wall-shedding rate of the high-initial-strength hot-melt adhesive can be greatly reduced. The synergistic effect of the two processes cannot be achieved by using only one of the processes. This shows that the filling process of the present invention is stable and can meet the demand for high-initial-strength hot-melt adhesive to prevent wall-shedding.

[0074] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A hot melt adhesive filling method, characterized in that: The following steps are involved: S101: preheating a hose for filling the hot melt adhesive so that the hose expands due to heat, wherein the preheating temperature is higher than the heating temperature of the hot melt adhesive; S102: Filling hot melt adhesive into the preheated hose; S103: Temporarily keeping the hose filled with hot melt adhesive warm; S104: Repeat S101-S103 to continue filling and keeping the next tube warm until the number of filled and kept warm reaches the target number; S105: After the target number of tubes are filled, the tubes that are temporarily kept warm are placed in a cooling device and cooled to room temperature at a uniform speed. The contraction of the tubes caused by thermal expansion and cooling is much greater than the contraction caused by the hot melt adhesive cooling from liquid to paste or semi-solid. The hot melt adhesive filling device used to complete the hot melt adhesive filling method includes: Bracket; A plurality of heating and heat-insulating sleeves are rotatably mounted on the bracket and are provided with a rubber hose cavity, and a rubber inlet is provided at the bottom of the rubber hose cavity; A filling device is used to fill the hot melt adhesive into the hose in the hose cavity based on the glue inlet.

2. The hot melt adhesive filling method according to claim 1, characterized in that: The preheating temperature of the hose is higher than the temperature of the hot melt adhesive before filling.

3. The hot melt adhesive filling method according to claim 2, characterized in that: The preheating temperature of the hose is 5-10° C. higher than the temperature of the hot melt adhesive before filling.

4. The hot melt adhesive filling method according to claim 1, characterized in that: The temperature of the hot melt adhesive before filling is 80-150°C.

5. The hot melt adhesive filling method according to claim 4, characterized in that: The hose is cooled uniformly to room temperature at a rate of 10-20°C / Hour.

6. The hot melt adhesive filling method according to claim 1, characterized in that: The cooling device is an oven.

7. The hot melt adhesive filling method according to claim 1, characterized in that: The hot melt adhesive filling device also includes: The photoelectric sensor is used to align the hose with the specified position and identify the amount of glue filled in the hose.

8. The hot melt adhesive filling method according to claim 1, characterized in that: The hot melt adhesive filling device includes a glue feed channel and an opening and closing valve; a heat preservation device is provided on the outside of the glue feed channel; and the opening and closing valve is used to open and close the glue feed channel.

9. The hot melt adhesive filling method according to claim 1, characterized in that: When the rubber hose is in the rubber hose cavity, the distance between the side surface of the rubber hose and the heating and heat-insulating sleeve is 1-2 mm.

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