WO2022042115A1

WO2022042115A1 - Uniform heating method

Info

Publication number: WO2022042115A1
Application number: PCT/CN2021/106378
Authority: WO
Inventors: 林柏昌
Original assignee: 正合林兴业股份有限公司
Priority date: 2020-08-28
Filing date: 2021-07-15
Publication date: 2022-03-03
Also published as: CN114102961A

Abstract

Disclosed is a uniform heating method, the steps of which include: introducing an object to be heated into a mold, wherein the mold sequentially includes an upper cover, a middle cover and a lower cover, which can be combined with one another, the upper cover and the lower cover, the middle cover and the lower cover or the upper cover and the middle cover are in concave-convex fit so as to form a containing space therein, the object to be heated is introduced into the containing space, and the mold includes a part through which an internal heating source can penetrate; applying the internal heating source to the object to be heated for a specific processing time; and then cooling the object to be heated to obtain a heated object finished product. By means of the cooperation between the heating process and the mold provided in the present invention, the problem in the prior art of heating being prone to being nonuniform can be solved, and the problem in the prior art of a foamed body not being able to be effectively molded by means of a single heating source or cooperation between an internal heating source and an external heating source is solved.

Description

uniform heating method

technical field

The present invention provides a heating method, in particular to a method for uniform heating.

The heating method provided by the present invention is firstly applied to the fields of foam molding technology and food heating, and its technical content and implementation are described in detail below, but the present invention is not limited to this application or the finished product. Any form of equivalent change or product made falls within the scope of the present disclosure.

Background technique

Traditional foam molding methods are mostly processed in the form of external heating. Taking electrothermal heating as an example, by applying an electrothermal heating source outside the molding die, foam molding is performed in a high-temperature and high-pressure manner. Because the heating source is applied from the outside, Therefore, it takes a long heating time to wait for the heat to penetrate into the whole material. For partially crystalline or crystalline foamed materials and physical foamed materials, it is easy to cause the foaming material to be caused by various factors such as high pressure, excessive heating or insufficient heating. And have adverse effects on foam molding. The heating method that promotes the foaming of the foaming agent in the foaming material mainly relies on the conduction from the outside of the material to the inside through the heating conduction of the external heat source, which is easy to heat unevenly and makes the quality of the foaming material difficult to control.

Taking the technology of forming the foam material of expanded thermoplastic polyurethane (ETPU or expanded beads) into a cushion body, which is quite popular in recent years, as an example, after heating the mold and the foam material externally, the cross-sectional condition of the foam body is closer The foamed material of the mold is more easily affected by the temperature of external heating and is bonded and formed. The farther the temperature is from the mold, the lower the temperature received by the foamed material, and its molding is mostly false molding, and the bonding strength is low. And it is easy to be peeled off under the influence of external force, and the foam material located at the center of the mold has a relatively low probability of forming due to insufficient thermal conductivity, so it is mostly false forming or no forming. Based on this, there is an urgent need for a processing process and a suitable mold that can uniformly heat a substance, so as to solve or at least provide an improved alternative.

It should be noted that any technique mentioned above in the present invention is not an admission that it is all or a part of the basic knowledge or common knowledge in the field.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned problem that the existing single external heating source cannot effectively and uniformly form the foam, the present invention provides a uniform heating method to solve the above-mentioned technical problem.

The invention discloses a uniform heating method, the steps comprising:

introducing an object to be heated into a mold;

The mold includes an upper cover, a middle cover and a lower cover that can be combined with each other in sequence, wherein: the upper cover and the lower cover, the middle cover and the lower cover, or the upper cover and the middle cover are concave-convex fit and An accommodating space is formed therein, the object to be heated is introduced into the accommodating space, and the mold includes a portion through which an internal heating source is permeable;

After applying the internal heating to the object to be heated resulting from a specified processing time; and

After the object to be heated is cooled, a finished object to be heated is obtained.

Wherein, after the internal heating is applied to the object to be heated from a specific processing time, another internal heating source or an external heating is further applied from another specific processing time.

Wherein, a heating auxiliary energy is applied to the internal heating source and/or the external heating source at the same time, and the heating auxiliary energy is an electrostatic field.

Wherein, a cooling step is performed after applying the internal heating source; or, a cooling step is performed after applying the internal heating source and/or the external heating source.

Wherein, the external heating source is hot water heating, steam heating, resistance heating component heating, thermal heating, conductive heating, induction electromagnetic heating, capacitive dielectric heating, electric heating tube heating, hot air heating, hot oil heating; and the internal heating source For radiation heating, including infrared (IR) heating, radio frequency radiation (RF) heating, microwave (MW) heating.

Wherein, the object to be heated includes a foamed material or a food, and the foamed material is in a non-foamed, micro-foamed, and foamed state.

Wherein, the middle cover and the upper cover or the lower cover of the mold are in a concave-convex matching relationship including a screw-thread structure and a retractable structure to compress the space for the object to be heated in the accommodating space.

Wherein, the mold material is plastic, rubber, silica gel, silicone rubber, glass, ceramic, metal or composite alloy material.

Wherein, the mold further includes a temperature monitoring device.

As can be seen from the above description, the present invention has the following advantages and advantages:

1. When the heating process provided by the present invention is matched with the mold, it can improve the problem that the existing technology is easy to heat unevenly, and the existing technology can not effectively form the foam by the combination of a single heating source or two internal and external heating sources. question.

2. The present invention can further make the foamed material and the mold more closely contacted by mold clamping, high-pressure filling or pressing action, and after removing the air or pores between the materials, the surface layer of the foamed material can be formed by external heating. , and the internal pseudo-forming, and then the internal heating method is used to make the internal foam material bond and form; or the internal heating method can be used to form the internal foam material, and then the external heating method can be used to form the surface layer of the foam. A more uniform foaming effect can be achieved, thereby improving the above-mentioned problems.

Description of drawings

Fig. 1 is the flow chart of the first preferred embodiment of the present invention;

Fig. 2 is the flow chart of the second preferred embodiment of the present invention;

3 is a schematic diagram of the first preferred embodiment of the applicable mold of the present invention;

4 is a schematic diagram of the second preferred embodiment of the applicable mold of the present invention;

5A to 5B are cross-sectional SEM images of the foamed molded body made by the foaming method provided by the present invention (FIG. 5A is a magnification of 50, and FIG. 5B is a magnification of 100);

6A-6B are cross-sectional SEM images of the foamed molded body with insufficient foaming produced by the existing single heating source (FIG. 6A is a magnification of 50, and FIG. 6B is a magnification of 100);

FIGS. 7A to 7B are cross-sectional SEM images of the over-foamed foamed molded body produced by the existing single heat source ( FIG. 7A is a magnification of 50 , and FIG. 7B is a magnification of 100 ).

Symbol Description:

S1～S5 foam molding steps

11 top cover

111 Top cover thread

13 Lower cover

131 Lower cover thread

14 middle cover

21 retractable parts

detailed description

In order to understand the technical features and practical effects of the present invention in more detail, and to implement them according to the contents of the description, the preferred embodiments shown in the drawings are further described in detail as follows.

Please refer to FIG. 1 , the first preferred embodiment of the present invention is a heating method for foaming molding by using the object to be heated as foam beads, and the steps include:

S1, introduce a foamed material (or can be referred to as the object to be heated), such as the foamed beads used in this embodiment, into a mold;

S2, applying a first heating energy to the foamed material;

S3, applying a second heating energy after the first heating energy is cooled or slightly cooled;

S4, after the second heating energy is cooled, a foamed molded body (or can be called a heated object) is obtained; and

S5. The foamed molded body is removed from the mold.

Wherein, the above-mentioned first heating energy and the second heating energy may be an external heating source, an internal heating source, or a combination of an internal heating source and an external heating source, respectively. The types of the external heating source may include but are not limited to hot water heating, steam heating, resistance heating components, thermal power, conductive heating (ohmic heating), induction heating (electromagnetic heating), capacitive heating (dielectric heating), electric heating tube heating , hot air heating, hot oil heating, etc. Preferred embodiments of the internal heating source are in the form of infrared (IR) heating, radio frequency radiation (RF) heating, microwave (MW) heating, and the like. In other beneficial situations of the present invention, when applying the first and second heating energy, a heating auxiliary energy can be applied at the same time, such as applying an electrostatic field, which can be a low-voltage or high-voltage electrostatic field to increase the liquid content in the heated object. (such as water) evaporation efficiency, so that the particle size of the droplet/vapor after the liquid is evaporated and/or the particle size of the heating vapor from the external heating source is smaller, and the particle size is more uniformly distributed among the objects to be heated , Under the action of heating, it will help to shorten the process time and improve the heating uniformity.

The so-called internal energy in the present invention refers to the internal heating effect that the heating source will drive the material molecules to vibrate or move, causing the material molecules to rub and generate heat. The so-called external heating refers to the material that the heating source can conduct heat through the mold, and the heat of the heating source is transferred to the surface of the material to produce a heating effect.

In the most preferred case of the present invention, the internal heating source is used for heating first, and then another internal heating source or an external heating source is used for heating to achieve the effect of uniform heating. Then at least the material that can make the internal heating source transparent, and other parts can be made of relatively durable materials, such as high-strength plastic or metal.

In this embodiment, if the first heating energy is first selected as the external heating source, and the second heating energy is the internal heating source, the main foaming heating mechanism is to first use the external heating source to foam the foam. The surface of the beads is heated to form a continuously bonded skin layer, and the foamed beads inside may be partially pseudo-bonded or non-bonded, and then the second heating energy is used as the internal heating source to heat the foamed beads inside. Foam molding. In this way, the foamed molded body can have a uniform foaming effect, and the problem of pseudo-molding or non-molding in the prior art can be improved. In this embodiment, the above-mentioned first heating energy can also be selected as the external heating source and the second heating energy can be replaced by the internal heating source, and the foamed molded body with uniform foaming effect can still be obtained.

Please refer to FIG. 2 , the second preferred embodiment of the present invention also uses the object to be heated as the foamed beads as the foamed material, and is described in the form of two-stage heating energy but different heating timings. The steps of this embodiment are described. Include:

S1, introduce this foaming material into this mould;

S2, after applying the first heating energy to the foamed material for a specific processing time;

S3, then applying the second heating energy to the foamed material for another specific processing time;

S4, after the first heating energy and the second heating energy are both cooled to obtain the foam molding;

S5. The foamed molded body is removed from the mold.

In this embodiment, the so-called specific processing time of S2 and S3 is determined according to the characteristics of the foamed material and the state to be formed each time. Usually, the longer the processing time, the higher the foaming ratio, or the foamed beads. Products with a higher inter-melt bond/bond state. Similar to the above-mentioned first preferred embodiment, this embodiment achieves the effect of uniform heating by applying two-stage heating energy to the foamed material, but is different from the above-mentioned first preferred embodiment in that the During the process of applying the first heating energy and the second heating energy, there is a partial overlapping heating time, which can provide a higher-intensity heating method, which is suitable for foaming materials requiring relatively high-intensity heating energy. Similarly, in this embodiment, when the first heating energy and the second heating energy are applied, heating auxiliary energy can be applied to improve the uniformity of energy distribution

The first heating energy and the second heating energy used in this embodiment can be selected from a combination of an external heating source and an internal heating source. According to the characteristics of the foamed material to be molded, different heating sources can be adaptively selected and two types of heating sources can be selected. Heating molding is carried out in stages, or even multi-stage methods, to improve the problem of false molding or no molding, and provide a more uniform foam molding effect.

Further, when the foamed material of the present invention is introduced into the mold, the foamed material can be brought into closer contact with the mold through high-pressure filling or pressurization after the mold is clamped, and the air or pores between the materials can be removed before removing the foamed material. The two-stage or multi-stage heating step of the present invention is performed, so that the heat energy can be conducted more uniformly to the foamed material. In addition to the high pressure filling or pressurizing action after mold clamping, the above-mentioned mold can make the foam material more closely adhere to the mold. Generally, it has a retractable structure, and additional pressure on the foam material makes the space in the mold accommodating the foam material more compressed, so as to achieve the same effect of making the foam material more closely to the mold.

In detail, the above-mentioned mold has a screwable structure as shown in FIG. 3 , and may have an upper cover 11 and a lower cover 13 . The outer surface also has a lower cover thread 131. The upper cover thread 111 and the lower cover thread 131 can be screwed together to change the size of the accommodating space for the foamed material, thereby enhancing the heat conduction effect of the foamed material. More preferably, the upper cover 11 and the lower cover 13 have a concave-convex structural relationship. For example, the bottom of the upper cover 11 is preferably convex and can cover the inner concave portion of the lower cover 13 to form the container. set space. Further, another preferred solution is that a middle cover 14 can be optionally added between the upper cover 11 and the lower cover 13 , and the upper cover 11 can optionally not have a convex structure, but instead The middle cover 14 has a protruding structure, and the middle cover 14 and the lower cover 13 form the accommodating space. Similarly, the size of the closed space inside the mold for accommodating the foamed material can be changed, and the foamed material can reach different degrees. pressurized. The same preferred solution is that the above-mentioned accessories included in the mold, the upper cover 11 and the middle cover 14 also include a accommodating space, and the object to be heated can also be selectively put into the upper cover 11 and the middle cover The accommodating space formed by the 14 rooms is heated, which is selected based on the needs of the applicator, which is not limited.

As shown in FIG. 4, for the design of the mold with a retractable structure, after the upper cover 11 and the lower cover 13 are correspondingly closed, a retractable part 21 that can be extended and retracted inside the mold and change the size of the space is further provided. Applying external pressure to the retractable member 21 can correspondingly reduce the space inside the mold, and apply pressure to the foamed material, so as to make the foamed material more closely to the mold and better heat transfer effect.

The present invention is suitable for the above-mentioned foaming mold of the foamed material. According to the difference in the form of the heating source used, the material can preferably be selected from plastic/resin (including fluorine-containing resin, such as Teflon), rubber, silica gel, silicon Rubber, glass, ceramic, metal, composite alloy materials or a combination of the above materials are used to match the different heating source forms selected. The foam material is placed in the accommodating space formed by the concavo-convex fit of the upper cover 11 , the middle cover 14 and/or the lower cover 13 , and the protruding part of the upper cover 11 or the middle cover 14 can be pressed down The foam material is fixed so that it can evenly cover the lower cover 13 to achieve a more uniform heating effect. The upper cover 11 or the middle cover 12 can be pressurized by an external mechanical force such as pneumatic, electric or hydraulic, so that it can effectively cover the lower cover 13 .

Further, in the present invention, when the outer surface of the upper cover 11 and the inner surface of the lower cover part 13 have matching threaded structures (111, 131), the middle cover 12 is preferably used in combination, and the middle cover 12 is mounted on the lower cover After 13, it will not rotate in conjunction with the upper cover 11, so it can be formed into a non-circular or other asymmetric structure, and the uniformity of heating and the molding effect can be regulated by the degree of rotation and pressing of the upper cover 11.

Further, the lower cover 13 of the present invention can be equipped with a temperature monitoring device, which can monitor the heating temperature in real time during the manufacturing process.

In addition, corresponding to the above-mentioned process and mold, the foam material used in the present invention is compressible before processing, and can be basically divided into three types. The state of incomplete foaming or micro-foaming before the mold, and the third is the state of foaming before entering the mold. The so-called non-foamed state means that the foamed material does not foam in the kneading step before the heating process provided by the present invention; and the foam is not completely foamed or the foamed material is introduced into the provided by the present invention. The mixing step before the heating process has foamed, but the foaming is not complete (or can be called micro-foaming), for example, the foaming agent is not fully reacted or two or more high and low temperature foaming agents are added. The material can be in the state of micro-foam with small particles; the foamed material means that the foamed material has been foamed before being introduced into the heating process provided by the present invention. Melt extrusion granulation/plate, high pressure fluid impregnation, dissolution equilibrium, primary heating foaming, secondary heating foaming, pressure-loading treatment and other technologies to generate foamed materials, for example, it is preferable to form foamed materials such as supercritical fluids Foamed beads, or foamed thermoplastic polyurethane (E-TPU), preferably in the form of beads, plates, strips, stars or other forms.

The foaming molding technology provided by the present invention is suitable for physical foaming materials or chemical foaming materials, and according to different types of heating sources selected, additives that can lead to faster and more uniform heat transfer and conduction can be added correspondingly. . For example, if the internal heating source selected as the heating source of the foamed material is microwave, a component capable of generating microwave resonance heating, such as water or liquid, can be added to the foamed material, so that the heating foaming molding of the present invention can be improved. The heat is more uniformly transmitted during the time, and a more excellent foam molding effect is obtained. In addition to the foamed beads described in the above two preferred embodiments, the foamed material may also be a normally molten foamed material or a foamed material that has been in a semi-foamed state, which is not limited thereto.

The foamed molded body treated by the heating method of the present invention can be divided into a continuous foamed structure and a discontinuous foamed structure. The so-called continuous foamed structure means that the unfoamed foam material is added into the mold Carry out foaming, and the foaming structure of the obtained foamed molding is continuous; and the so-called discontinuous foaming structure refers to the use of the above-mentioned incomplete foaming/micro-foaming and the foamed material that has been fully foamed, using The heating process provided by the present invention completes the foamed molded body, so that the incompletely foamed foamed material can be foamed again or the foamed foamed materials can be bonded to each other to obtain the foamed molded body.

Utilizing the above-mentioned mold, the present invention provides a third preferred embodiment that can also achieve a uniform heating effect, the steps of which include:

Introducing an object to be heated, such as the expanded beads used in this embodiment, into a mold;

The mold includes the upper cover 11 , the middle cover 14 and the lower cover 13 which can be combined with each other in sequence, wherein: the upper cover 11 and the lower cover 13 , the middle cover 14 and the lower cover 13 or the upper cover Between 11 and the middle cover 14, a concave-convex fit can be formed simultaneously or separately to form the accommodating space, and the object to be heated is introduced into the accommodating space;

In this embodiment, the mold preferably includes a portion that allows the internal heating source to pass through. For example, the upper cover 11 and the middle cover 14 may include a portion that allows the internal heating source to pass through.

Then, after applying the internal heating source to the foamed material for a period of time, the object to be heated can also be uniformly heated through the close fit between the mold parts and the efficient conduction of heat, and there is no need to apply two heating sources as described above. Or multi-stage heating steps can achieve the same uniform heating effect.

Please refer to FIGS. 5A-5B, 6A-6B and 7A-7B, which are cross-sectional SEM images of the foamed molded body produced by the foaming method provided by the present invention (FIG. 5A is a magnification of 50, FIG. 5B is a For the magnification of 100), the cross-sectional SEM image of the foamed molded body with insufficient foaming made by a single heating source (Fig. 6A is a magnification of 50, Fig. 6B is a magnification of 100), and the foaming molding with excessive foaming SEM images of the body cross section (Fig. 7A is a magnification of 50, and Fig. 7B is a magnification of 100). First, the foamed molded body of the present invention shown in FIGS. 5A to 5B has uniform and small cells, which means that the heating is uniform and the moldability is good. On the other hand, looking at the foamed moldings of FIGS. 6A to 6B and 7A to 7B, although the appearance of the finished product is no different from that of the present invention, under the same magnification in the cross-section, the foamed cells are large and uneven, indicating that the more serious the collapse, the insufficient molding Or overmolding, mainly due to gas agglomeration due to high internal temperature. It can be seen from this that the heating method provided by the present invention can indeed achieve a more uniform and excellent foaming effect compared with the conventional heating technology.

The uniform heating method provided by the present invention can be applied to the manufacture of various foamed products such as micro-foaming, low-foaming or high-foaming, including floor mats, insoles or mattresses, etc. The heating method can also be extended to other heating On demand, such as in the field of food heating.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the scope of the claims of the present invention. All other equivalent changes or modifications without departing from the spirit disclosed by the present invention shall be included in the present invention. within the scope of the patent application.

Claims

A method for uniform heating, characterized in that the steps comprise:

introducing an object to be heated into a mold;

The mold includes an upper cover, a middle cover and a lower cover that can be combined with each other in sequence, wherein: the upper cover and the lower cover, the middle cover and the lower cover, or the upper cover and the middle cover are concave-convex fit and An accommodating space is formed therein, the object to be heated is introduced into the accommodating space, and the mold includes a portion through which an internal heating source is permeable;

After applying the internal heating to the object to be heated resulting from a specified processing time; and

After the object to be heated is cooled, a finished object to be heated is obtained.
The uniform heating method of claim 1, wherein after the internal heating is applied to the object to be heated from a specific processing time, another internal heating source or an external heating is further applied from another specific processing time time.
The uniform heating method according to claim 2, wherein a heating auxiliary energy is applied to the internal heating source and/or the external heating source simultaneously, and the heating auxiliary energy is an electrostatic field.
The uniform heating method of claim 1, wherein a cooling step is performed after the internal heating source is applied.
The uniform heating method according to claim 2 or 3, wherein a cooling step is performed after applying the internal heating source and/or the external heating source.
The uniform heating method according to claim 2 or 3, wherein the external heating source is hot water heating, steam heating, resistance heating element heating, thermal heating, conductive heating, induction electromagnetic heating, capacitive dielectric heating, electric heating Tube heating, infrared heating, hot air heating, hot oil heating; and the internal heating source is radiation heating, including infrared heating, radio frequency radiation heating, and microwave heating.
The uniform heating method according to claim 1, 2, 3 or 4, wherein the object to be heated comprises a foamed material or a food, and the foamed material is non-foamed, micro-foamed, or foamed condition.
The uniform heating method according to claim 1, 2, 3 or 4, wherein the concave-convex matching relationship formed by the mold comprises a screw-thread structure and a retractable structure, so as to compress the to-be-to-be accommodated in the accommodating space. The size of the space to be heated.
The uniform heating method according to claim 8, wherein the material of the mold is plastic, rubber, silica gel, silicone rubber, glass, ceramic, metal or composite alloy material.
The uniform heating method according to claim 1, 2, 3 or 4, wherein the mold further comprises a temperature monitoring device.