JPH0481926B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a slush molding method for skin materials and a molding apparatus thereof, and in particular, the present invention is directed to slush molding of thick skin materials. An example of a skin material is a skin body that is a part of automobile interior parts such as console boxes, instrument panel pads, and glove boxes.As a final product, this skin material includes a foam layer, a shape-retaining core, etc. This is a member for covering the outside of the material.

(Prior art) Molding of skin materials by slush molding is a relatively simple method that allows for accurate production of skin materials with precise surface patterns. It is widely used in various industrial fields.

Conventional slush molding includes a method in which a heating oil supply pipe is installed on the back of the mold, a method in which heating wires are buried in the mold, and a method in which a heating wire is buried in the mold, as shown in Japanese Patent Publication No. 54-10581. Vinyl chloride is placed in a mold that is heated from the back side by bringing the back side of the mold directly close to the flame, or by immersing the back side of the mold in heat transfer oil or heated metal powder. After putting resin plastisol or powder into a mold and partially gelling or semi-melting the material on the molding cavity surface of the mold, the excess material is discharged and the mold is further removed. After the molten adhesive resin is solidified by heating, the mold is cooled to complete the skin material.

(Problems to be solved by the invention) In recent years, as consumer tastes have become more sophisticated and diversified,
These skin materials are also required to be of higher quality and heavier, and there is an increasing demand for skin materials themselves that are thicker, or for composite skin materials such as different materials or solid layers and foam layers. When manufacturing a thick skin material using slush molding, heating only from the back side of the mold makes it difficult to heat the skin material uniformly over the entire area, resulting in a uniform skin. We have seen the emergence of problems that need to be resolved when obtaining timber.

In particular, when molding a skin material with a foam layer on the inside, the portion of the foam layer away from the molding cavity surface of the mold is insufficiently heated, resulting in uneven foaming and making it difficult to obtain a homogeneous product. was difficult. In addition, in the manufacturing process of composite skin materials, after the surface layer is temporarily formed, a different material is layered on the inside and heat treated again. Since the temperature is about 0.031Kcal/m・Hr℃, the inner layer is not sufficiently gelled or melted and foamed, making it difficult to obtain a high-quality product. If the temperature of the mold is forcibly raised to increase the temperature, the surface layer in contact with the cavity surface of the mold will be locally overheated, resulting in deterioration of the layer.

One way to solve these problems is to heat-form from both the inside and outside of the mold by placing the mold itself, which has the raw material fused onto the molding cavity surface, into an open chamber set at a high temperature in advance. Proposed. However, in this case, it is certainly an effective method when the molded product is small, but for large molded products such as automobile console boxes, crash pads, and door trims, a large oven is naturally required. However, it is also inconvenient to handle, and problems remain as a practical solution.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems inherent in conventional slush forming means and to provide a simple slush forming method and apparatus for the same, regardless of the size of the molded product.

(Means for Solving the Problems) In order to achieve this object, the present invention has the following configuration. That is, the first aspect of the present invention is to preheat a slush molding mold equipped with a temperature control mechanism as necessary, to charge a resin material into a molding cavity of the mold, and to heat the mold. After the material is adhered to the cavity surface in a semi-molten state, the excess material is discharged from the mold, and while the mold itself is heated, the heating medium is also ejected onto the surface of the adhesive resin material on the cavity surface, The second invention is a slush molding method comprising a step of cooling the mold after curing the adhesive material, and the second invention is such that the molding section includes a slush molding mold and a heating device that ejects heat toward the back of the mold. and a cooling medium generator, and a box-shaped auxiliary heating section that completely covers the molding cavity surface of the mold of the molding section and that can be connected to and separated from the molding section is provided with the molding section inside the box. The slush molding apparatus is equipped with an introduction member for guiding and ejecting a portion of the heating medium generated by the heating medium onto the cavity surface of the mold.

(Function) The slush molding mold is preheated by jetting a heating medium onto the back side of the mold as necessary.
A thermoplastic resin powder material is put into the cavity of the mold, and the mold is heated. A portion of the powder resin adheres to the molding cavity surface of the mold in a semi-gelled, semi-molten state. Excess resin material is then drained, leaving the molten resin on the cavity surface.
Next, a box-shaped auxiliary heating part is attached to the cavity side of the mold, its periphery is kept airtight, and an appropriate space is left inside for a heat medium flow path, and the back side of the mold is The curing work progresses by spouting a heating medium for finishing from the side, and at the same time, a part of this heating medium is branched and supplied to the box-shaped auxiliary heating section.
Guided by the introduction member installed in the auxiliary heating section,
The injection is applied directly to the cavity surface of the mold, or more precisely, to the inner surface of the target skin, and the mold is heated from both the front and back sides, so even if the skin is somewhat thick, it will be uniform everywhere. It is possible to mold products. After heating, a cooling medium is injected onto the back side of the mold and, if necessary, onto the cavity surface of the mold, and the molded skin body is removed from the mold.

(Example) Next, a plurality of specific devices for carrying out the slush molding method for skin materials according to the present invention will be described with reference to the drawings.

In the figure, 1 is a forming section equipped with a main heating mechanism;
A generally rectangular box 3 made of metal such as aluminum or a part of it made of synthetic resin, preferably coated with glass wool, asbestos, etc. on the inner or outer surface and heat-insulated, is made of nickel, aluminum, copper, A slush molding die 4, which is usually 2 to 5 mm thick and made of other metals or alloys thereof and formed by electroforming or the like, is assembled by fitting from the back side 5 of the die.

Hollow rotating shafts 6 and 7 that communicate with the inside of the box 3 are fixed to the left and right sides of the box 3, and the molding section 1, which is mainly composed of the box 3 and the mold 4, has a pair of left and right supports 8. ，
The hollow rotating shafts 6, 7 are supported by a pair of bearings 9, 9 installed on the shaft 8, and the gear 11 fixed to the right rotating shaft 7 is connected to a reduction motor 13 installed on a bracket 12 on the support column 8. Gear 1 on the rotating shaft 14 of
5 to impart rotational and oscillating motion to the molded portion 1. The end of the left hollow rotary shaft 6 communicates with a manifold 17 installed in the box 3, and a large number of nozzle groups 18 protrude from the manifold 17 so as to cover substantially the entire rear surface of the mold 4. .

The outer ends of the left hollow rotating shaft 6, which serves exclusively as a heating or cooling medium supply port, and the right hollow rotating shaft 7, which also serves as a medium outlet, are connected via rotary pipe joints 20 and 21, respectively. As shown in detail in FIG. 3 and an example thereof, a heating and cooling duct circuit using a gaseous (air) medium is installed outside the molding section 1.

First, the heating duct circuit 23 is connected to the air supply rotary pipe via a valve 24, a heating blower 25, a heating heat exchanger 26, and a valve 27 to a duct extending from the exhaust rotary pipe joint 21. Joint 2
It forms a circulation circuit to 0.

Next, in the cooling duct circuit 29, a duct extending from the exhaust rotary pipe joint 21 branches at a position before the valve 24, and the duct portion includes a valve 30, a cooling blower 31, and a cooling heat exchanger. They join together at a duct portion that also serves as a heating duct circuit at a position closer to the air supply rotary piping joint 20 than the valve 27 through a vessel 32 and a valve 33.

As the heat exchangers 26 and 32, for example,
The heating heat exchanger 25 is composed of pipes in which a large number of electric heaters 26A with fins are stacked, and the cooling heat exchanger 32 is composed of pipes in which finned cooling water pipes 32A are stacked in multiple layers. urge

Reference numeral 35 denotes a box-shaped auxiliary heating section that corresponds to the molding section 1 and in particular injects a curing heating medium onto the molding cavity surface of the mold 4; Trolley 39 running above
Packing material 37 is placed around the upper surface of the box 36, which is installed on the lifting device placed above, for example, the rods 41, 41 of a pair of pneumatic cylinders 40, 40, and has been moved directly below the molding section 1. The auxiliary heating section 35 is attached to the rod 4 of the pneumatic cylinder 40.
As the molded part 1 expands, the periphery of the molded part is joined to the box 3 part through the packing material 37 in a sealed state.

A heating medium introduction member 43 is installed in this box-shaped auxiliary heating section 35, and the heating medium generated in the molding section 1 is directed and guided by the introduction member 43 toward the molding cavity surface of the mold. And let it gush out without wasting anything.

Next, a description will be given of a mechanism for supplying an auxiliary heating medium to which a part of the heating medium generated in the molding section 1 and ejected to the back surface of the mold is branched.

From the manifold 17 installed in the box 3 constituting the molding section 1, when the molding section 1 and the box-shaped auxiliary heating section 35 are joined, a supply pipe 44 and a supply pipe 44 are provided to divert the heating medium to the auxiliary heating section. A discharge pipe 45 for supplying the heated and used heating medium to the discharge hollow rotary shaft 7 is installed in the box part 3 of the molding part 1. Each of the supply pipe 44 and the discharge pipe 45 has a valve 4 operated by an actuator 46.
7 and 48 are installed, and these valves 47 and 48 including the actuator 46 are preferably subjected to heat insulation treatment in consideration of their heat resistance. If this is difficult, insulation treatment may be applied to only the actuator 46. However, if this is not possible, it is also necessary to consider installing the supply pipe 44 and the discharge pipe 45 outside the box 3 constituting the molding section 1.

Next, a specific example of the heating medium introducing member 43 provided in the box-shaped auxiliary heating section 35 will be disclosed.
Introducing member 43 in Figures 2 and 3.
The entire box of the auxiliary heating section is a heat storage tank 53, and the inlet 49 provided in the heat storage tank 53 and the supply pipe 44 of the forming section 1 are connected between the forming section 1 and the auxiliary heating section. At the time of joining, leaving a sufficient space 50 to serve as a flow path for the heat medium, communication occurs, and the heat storage tank 53
The bulging portion 51 that is raised from a portion of the molding portion 1 is fitted into the mold 4 of the molding portion 1 with a sufficient gap left therebetween;
A heating medium is injected into the mold 4 from a group of jet holes 52 formed on the top surface of the bulging part 51, and the heating medium after being injected into the mold 4 is passed through the discharge pipe 45 of the molding part 1. It is collected and discharged.

As for another embodiment centered on the heating medium introducing member 43, in FIG. By forming a concave deflection partition plate 54 on the surface facing the molded body 1 in such a manner that it can be held in place and cover substantially the entire area of the mold 4, another embodiment is as shown in FIG. , a small manifold 55 is installed in the box 36 of the auxiliary heating section 35, and when the compact 1 and the auxiliary heating section 35 are joined, the inlet 57 of the small manifold 55 communicates with the supply pipe 44 of the compact 1. However, a group of nozzles 56 protruding from the manifold 55 is configured to cover substantially the entire molding cavity surface of the mold 4.

Still another embodiment, as shown in FIG. 6, can be said to be a modification of the introduction member 43 shown in FIG. The introduction pipe 59 provided in the box 36 of the auxiliary heating unit 35 that communicates with the supply pipe 44 of the molding unit 1 is provided with a ball valve 61 that can maintain only the pipe opening closed using the pressing force of a spring 60. In addition, a small closed heat storage chamber 62 that can penetrate into the mold 4 and leave a sufficient gap between it and the mold 4 is protruded from a part of the heat storage tank 58. A group of ejection ports 63 for ejecting a heating medium toward the cavity surface of the mold is provided on the top surface of the heat storage chamber 62.
A small inlet pipe 64 that serves as a communication port with a heat storage tank 58 having a box has a built-in small ball valve 66 that can maintain only the pipe opening closed using the pressing force of a spring 65. It's forcing me. Instead of the ball valve 61, 66 mechanism illustrated above, a valve using a reed,
Alternatively, an automatic valve may be used.

Next, operations in a general process of slush forming using the apparatus according to the present invention will be explained step by step.

First, in the state shown in FIGS. 1 and 3, the supply pipe 44 and the discharge pipe 4 provided in the molding section 1 are
Close the valves 47, 48 in 5 and the valves 24, 27 integrated in the heating duct circuit 23 in the external duct circuit
At this time, the valves 30 and 33 incorporated in the cooling duct circuit 29 are closed. Heating heat exchanger 26
The hot air is stored in the manifold 17 via the valve 27, the rotary piping joint 20, and the hollow rotating shaft 6 by driving the blower 25, and then the hot air is stored in the manifold 17 through the nozzle 18.
The water is ejected to almost the entire area of the back of the mold 4, and the mold 4
is heated. The ejected heating medium fills the box 3 constituting the molding section 1, and is then sucked and collected by the blower 25 via the hollow rotating shaft 7 and the rotary piping joints 21 and 24.

The mold 4, which is preheated to 200°C to 300°C and forms part of the molding section 1, is connected to the gear group 11 of the electric motor 13,
By rotating around the rotation shafts 6 and 7 via the rotary shafts 15, plastisol or powdered vinyl chloride resin, ABS resin, or other thermoplastic resin is placed in the mold 4 with the molding cavity surface facing upward. Insert the
After that, the electric motor 13 is driven to cause the mold to swing.
By applying rotational motion, the powder material is deposited in a semi-gelled or semi-molten state over the details of the molding cavity surface of the mold, and the excess material is removed by rotating the mold downward. is discharged into a container located at

In addition, in the work of charging materials into the mold 4, a reservoir tank containing raw materials is placed directly below the mold 4, which is positioned facing downward, and the tank and the mold are assembled together to form the molding section 1. The box 3 and the reservoir tank are connected and integrated using a clamp or the like, and the box forming part 1 is assembled together with the reservoir tank.
After making the material adhere to the molding cavity surface of the mold 4 in a semi-gelled or semi-molten state by rotating it 180 degrees and rocking it, the molding part 1 together with the reservoir tank is rotated and returned to its original position. The mold 4 with the reservoir tank separated is placed on standby for the next process with the molding cavity surface facing downward.

A box-shaped auxiliary heating section 35 installed on a lifting device on a trolley 39 moving on tracks 38, 38 is located directly below the molding section 1, and is placed above the lifting device, for example, a rod 41 of a pneumatic cylinder 40. Along with the stretching movement, the auxiliary heating section 35
The peripheral edge thereof is joined to the lower surface of the molding section 1 through a packing material 37 while maintaining a sealed state, and at this time, the supply pipe 44 of the molding section 1 is connected to the heating medium introduction member 43 of the auxiliary heating section 35. Then, the valves 47 and 48 in the supply pipe 44 and the discharge pipe 45, which had been closed, are opened, as are the valves 27 and 24 in the heating duct circuit 23. The introduction member 43 of the auxiliary heating section 35 is as described in detail in multiple examples, but in FIGS. 1 to 3, the supply pipe 44 of the forming section 1 communicates with the heat storage tank 48. The heating medium pressurized in the heat storage tank 48 is then passed through the group of ejection holes 52 of the bulging portion 51, and the resin material in a semi-molten state previously attached to the molding cavity surface of the mold 4 is melted into gold. In addition to the heating from the back of the mold, the molding cavity surface, more precisely, the inner surface of the skin material, is simultaneously heated. The heat medium used to heat the skin material is applied to the space 5 formed between the molded body 1 and the auxiliary heating section 35 when they are joined together.
0, reaches the discharge pipe 45, and returns again to the heating blower 25 and the heating heat exchanger 26, thereby performing cyclical reuse that eliminates loss of thermal energy.
After heating and solidifying the skin material, the auxiliary heating section 35 and the forming section 1 are separated, the valves 27 and 24 in the heating duct circuit 23 are closed, and then the cooling duct circuit 2
Open the valves 33 and 30 in the supply pipe 44 and the discharge pipe 45, and start the cooling blower 31 and the heat exchanger 32. Cooling, and in turn cooling the epidermis. Note that while the auxiliary heating section 35 and the forming section 1 are connected, the supply pipe 44, the valve 47 in the discharge pipe 45,
48 can be opened to perform cooling work from both the front and back sides of the mold. On the contrary, the cooling capacity may be reduced, so care must be taken in this regard. Alternatively, a configuration may be adopted in which the cooling medium used in the cooling operation is discharged into the atmosphere without being returned to the cooling blower 31.

Further, when the heating medium copper introduction member 43 is configured with the concave deflection diaphragm 54 shown in FIG. After that, the partition plate 5
4 as a guide, the liquid flows over the entire surface of the molding cavity of the mold 4.

Furthermore, when the heating medium introduction member 43 is configured with the manifold 55 shown in FIG.
A pair of manifolds 17, 5 are installed on both the front and back sides of the
The heating medium is injected through groups of nozzles 18 and 56 that protrude from the nozzles 5 and 5, respectively.

In addition, the heat storage tank 58 and heat storage chamber 62, which are divided into two large and small sections in FIG.
62, the heating medium is injected onto the mold surface in a sufficiently pressurized state.

The above embodiment is just one embodiment of the present invention, and in particular, the opening/closing mechanism of the molding section 1 and the auxiliary heating section 35, the motor 13 of the molding section 1, the rotational oscillation mechanism centered on the gears 15 and 11, and the heating The cooling medium generating device, the means for supplying the heating medium to the molding section 1, and the means for heating and cooling the mold for slush are merely disclosed as one example.

For example, the opening/closing mechanism of the molding section 1 and the auxiliary heating section 35 may be achieved by using other actuators such as electric motors instead of the elevating mechanism by the cylinder 40, or by circular motion fixed by a hinge of a part of both components 1, 35. , it is also possible to have a structure that opens and closes this, and for the rotation mechanism of the molding section 1, instead of the transmission mechanism using gears 11 and 15, a chain, a belt, etc., or an actuator that performs linear motion such as a cylinder may be used. Good too.

Furthermore, as for the heating source of the heating medium generator, oil, gas, etc. may be used instead of the electric heater 26A, the atmosphere may be used as it is as a cooling source, and mist water may be used as a cooling source. It is possible. Alternatively, the heat medium may not be recovered and may be directly released into the atmosphere in the box of the molding section or the auxiliary heating section.

The heat medium to be used is not limited to the atmosphere, but other gases such as nitrogen may be used for the purpose of preventing oxidation of each component, and liquid may also be used as long as it does not adversely affect the skin material. do not have.

The heat medium is supplied to and discharged from the molding section using rotary piping joints 20, 21 and hollow rotating shafts 6, 7.
Alternatively, a hose or a tube may be used, or both may be used in combination.

As for the heating means for the slush molding die, the one shown in the example is the most practical in terms of equipment cost.
If we allow multiple heating and cooling systems,
It is also possible to provide the slush mold 4 with piping for passing a heat medium such as heat medium oil, steam, or cooling water hot gas, or to bury heating wires therein.

(Effects of the Invention) The slush molding method of the skin material according to the present invention applies conductive heating from the back side of the mold after discharging the excess resin material excluding the material adhered to the cavity surface of the mold after injection. The heating medium is also sprayed on the inner surface of the skin material, and the heating work is performed from both the front and back sides of the skin material, so the work efficiency is improved, and each part of the skin material is heated almost uniformly. Even in the case of a thick skin material, a laminated skin material with a foam layer inside, or a laminated skin material made of multiple types of resin materials, local overheating can be avoided and a high quality skin material that is homogeneous in each part can be molded. In addition, even when molding complex skin materials using highly uneven molds, melting and gelation of the skin material progresses approximately evenly in each location due to heat treatment from both the front and back surfaces of the skin material. The effect of promoting foaming is significant, and the effect is remarkable for skin materials that have a foam layer inside.

Furthermore, by controlling the amount of heating medium supplied from the inside of the skin material, the heating time, and the heating temperature, the foaming ratio can be controlled relatively easily, and fine quality control of the skin material becomes possible.

Further, the apparatus according to the present invention mainly includes a molding section that supplies a heating medium to the back side of the mold, and a box-shaped auxiliary heating section that can be joined and separated on the cavity surface side of the mold of the molding section. This auxiliary heating section is equipped with an introduction member for branching in a part of the heating medium generated in the molding section, and uses a single heating source to heat the heating medium from both the front and back sides of the mold. Since heat treatment can be performed at the same time, molding efficiency is improved and mechanical simplification is significantly effective.

In addition, the heating medium that is concentratedly ejected onto the cavity surface of the mold and heats the inner surface of the skin body is returned to the molding part side and reused, resulting in a remarkable effect on the effective use of energy without waste. can be expected.
In addition, this device is much smaller than the conventional method of heating the entire surface of the mold using an oven.
In addition, since the heating medium can be ejected in a concentrated manner on both sides of the mold, the thermal efficiency is good, the production space can be reduced, and the productivity is steadily increased.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view of the slush forming apparatus according to the present invention, showing the forming part and the auxiliary heating part immediately before they are joined, and Fig. 2 is the same as Fig. 1 showing the forming part and the auxiliary heating part in the joined state. Corresponding figures, FIG. 3 are front views centering on the heat medium duct circuit arranged in this device, and FIGS. 4 to 6 are views corresponding to FIG. 1 showing other embodiments. . In the figure, 1 is a molding part, 3 is a box, 4 is a mold for slush molding, 5 is the back of the mold, 6 and 7 are hollow rotating shafts, 17 is a manifold, 18 is a nozzle, 20,
21 is a rotary pipe joint, 23 is a heating duct circuit, 24 and 27 are valves, 25 is a heating blower, 2
6 is a heating heat exchanger, 29 is a cooling duct circuit,
30 and 33 are valves, 31 is a cooling blower, 32 is a cooling heat exchanger, 35 is an auxiliary heating section, 36 is a box,
37 is packing, 43 is a heating medium introduction member,
44 is a supply pipe, 45 is a discharge pipe, 47 and 48 are valves,
53, 58 are heat storage tanks, 49, 57 are inlets,
50 is a space part, 51 is a bulging part, 52 and 63 are jet holes, 54 is a concave deflection partition, 55 is a manifold,
56 is a nozzle, 59 and 64 are introduction pipes, 61 and 66
indicates a ball valve.

Claims (1)

[Claims] 1. A slush molding mold equipped with a temperature control mechanism is preheated as necessary, a resin material is put into the molding cavity of the mold, and the resin material is heated in a semi-molten state by heating the mold. After attaching the material to the cavity surface,
The skin coating consists of a process in which excess material is discharged from the mold, the mold itself is heated, and a heating medium is ejected onto the surface of the resin material adhered to the cavity surface, and the mold is cooled after curing the resin material adhered to the cavity surface. Slush forming method of wood. 2. The molding section consists of a slush molding die and a generating device for heating and cooling medium that is ejected toward the back side of the mold, while completely covering the molding cavity surface of the mold of the forming section, and The box-shaped auxiliary heating part that can be connected to and separated from the molding part is provided with an introduction member inside the box for guiding and ejecting a part of the heating medium generated in the molding part onto the cavity surface of the mold. Slush forming equipment for skin materials. 3. The back side of the slush molding die is fitted into a case, and the heating and cooling medium ejection part is housed in the case.
A slush forming device for skin material as described in Section 1. 4. A patent in which when the mold cavity surface side of the molding part and the auxiliary heating part are joined, the periphery of the joint part remains sealed, and an appropriate space is formed inside the joint part to serve as a flow path for the heat medium. A slush forming apparatus for skin material according to claim 2 or 3. 5. The heating medium introducing member of the auxiliary heating section is such that the box that constitutes the auxiliary heating section itself is a heat storage tank, and the surface of the bulging part that is raised in a part of the tank and fits into the mold cavity. A slush forming apparatus for a skin material according to any one of claims 2 to 4, wherein the slush forming apparatus is provided with a group of ejection holes opening toward the mold cavity surface. 6. Any one of claims 2 to 4, wherein the heating medium introducing member of the auxiliary heating section is configured with a concave deflection diaphragm installed at the joint surface of the box-shaped auxiliary heating section. The slush forming apparatus for skin material according to item 1. 7 The heating medium introducing member of the auxiliary heating section is constituted by a manifold provided with a group of nozzles facing the cavity surface of the mold.
A slush forming apparatus for a skin material according to any one of items 1 to 4. 8. The heating medium introducing member of the auxiliary heating section is such that the box that constitutes the auxiliary heating section itself is a heat storage tank, and a part of the tank fits into the cavity of the mold and has ejection holes directed toward the cavity surface. Claims 2 to 5 are provided with a chamber having a group of holes, and ball valves are provided in the heating medium introduction pipe to the heat storage tank and the heating medium introduction pipe to the chamber, respectively. A slush forming apparatus for a skin material according to any one of the items described in item 4. 9 A discharge pipe for discharging a heating and cooling medium communicates between the molding section and the auxiliary heating section, and further communicates with a discharge mechanism provided in the molding section.
A slush forming apparatus for a skin material according to any one of items 8 to 9. 10. The method according to any one of claims 2 to 9, wherein the heating medium ejected onto both the front and back surfaces of the mold in the molding section and the auxiliary heating section forms a circulating flow. Slush forming equipment for skin materials.