JP2002160238A - Method for analyzing flowability of polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for analyzing flowability particularly suitably employed as a method for observing a flow state of a molded item particularly molded in a mold suitable for mass production by analyzing a flow state of a polyurethane foam having an open cell structure or a closed cell structure with a fiber sensor. SOLUTION: An analyzing method for flowability of a polyurethane foam molded by use of a mold comprising a lower mold and an upper mold attachably/removably disposed to cover an open portion of the lower mold and form a closed space between the lower and upper molds, the mold having a cavity to which the polyurethane foam molding material is supplied, is conducted by attaching a fiber sensor at a predetermined position of the mold, supplying a polyurethane foam molding material to the mold, closing the mold and detecting a datum of the polyurethane foam material with the fiber sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flowability analysis method for analyzing the flow state of a polyurethane foam having an open-cell structure or a closed-cell structure using a fiber sensor.

[0002]

2. Description of the Related Art In general, molds for molding polyurethane foam are mainly made of aluminum. In addition, cutting from cast iron, forging, and solid aluminum is also known. I have.

By the way, the filling status of the foam inside the mold has not been confirmed very much. It is confirmed by a method (short shot) of flowing a foam material of a required amount or less, but it is difficult to grasp a phenomenon to be actually observed because the flow is different from an actual flow in a mold.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method for analyzing the fluidity of a polyurethane foam, which can visually analyze the fluidity of the polyurethane foam.

[0005]

Means for Solving the Problems In order to achieve the above object, the present inventor has conducted intensive studies, and as a result of further study on visualizing the internal foam material without providing a window material, A plurality of through-holes are provided at predetermined positions of the mold, and the through-holes are filled with a transparent resin, and a fiber sensor is attached to the transparent resin-filled portion in a non-contact state with the foam material in the mold to transfer form data. It was surprisingly found that the state inside the form can be visualized accurately and easily when detected.

In particular, the present inventors have found that the present invention can be suitably applied to a mold having a complicated cavity shape, such as a vehicle front seat, and have accomplished the present invention.

Accordingly, the present invention provides the following (1) or (2)
The present invention provides a method for analyzing the fluidity of a polyurethane foam. (1) A lower mold, an upper mold that is detachably provided to cover an opening of the lower mold, and forms an enclosed space between the lower mold and a closed space between the lower mold and the upper mold. Along with providing a through hole at a predetermined position of a mold to be a cavity to which a material for a foam molded product is supplied, filling the through hole with a transparent resin,
A polyurethane sensor is attached to the transparent resin-filled portion, the polyurethane foam material is supplied into the mold, the mold is closed, and then the data of the internal polyurethane foam material is detected by the fiber sensor. A method for analyzing the fluidity of a form. (2) The mold includes a core mold detachably provided in the closed space, and when the core mold is provided, low capacity is provided between the upper surface of the core mold and the lower surface of the upper mold. A cavity is formed, a large-capacity cavity is formed by the lower surface of the core mold and the upper surface of the lower mold, and a cavity having a structure in which the low-capacity cavity and the large-capacity cavity are connected via a gap. A method for analyzing the fluidity of the polyurethane foam according to claim 1.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The method of analyzing the fluidity of a polyurethane foam according to the present invention is to analyze the fluidity by attaching a fiber sensor to a known mold. is there.

Here, the structure of the fiber sensor will be described with reference to FIG. 1. FIG. 1 shows a front view (a) and a partially omitted side view (b) of the fiber sensor 1, respectively.

The fiber sensor 1 has an optical fiber cable 3 having two optical fibers 2 and 2 and emits light from one of the optical fibers and receives reflected light from the other optical fiber. is there. The distal ends of these optical fiber cables 3 are covered with a protective cover 5 made of polycarbonate having a screw portion 4 formed on the outer periphery. In addition, 6 is a mounting screw part.

The fiber sensor 1 can pick up an ON / OFF signal and has a structure capable of automatic control. Specific examples of the fiber sensor include a keyence digital laser sensor (non-contact sensor) and the like.

According to the method for analyzing the fluidity of a polyurethane foam of the present invention, a through-hole (screw hole) is formed in a known mold, a transparent resin is filled at the tip of the through-hole, and a fiber sensor is inserted into the hole. It is screwed and attached. In this case, in FIG. 1, it is preferable to fill a gap 7 in the tip of the protective cover 5 protruding forward from the tip of the cable 3 with a transparent resin, and screw it into the hole in this state.

The mounting position of the fiber sensor of the present invention on the mold is not particularly limited, and the mounting position can be appropriately determined according to the shape of the mold.

As the mounting position, for example, a position at which the material reaches the final position, a position at which molding defects easily occur, and the like can be selected.

In the analysis method of the present invention, in particular, the mold includes a core type removably provided in the closed space like a vehicle front seat, and the core type is provided. In this case, the core mold upper surface and the upper mold lower surface form a low-capacity cavity, and the core mold lower surface and the lower mold upper surface form a large-capacity cavity, and the low-capacity cavity and the large-capacity cavity are formed. This can be suitably adopted as a method of analyzing fluidity in a case where the and have a cavity having a structure connected via a gap.

The fiber sensor 1 of the present invention can be mounted by forming a through hole having a diameter of about 10 mm at a predetermined position of a mold used for molding, and mounting the fiber sensor 1 in the through hole. it can. The number of the sensors 1 to be attached is not particularly limited, and may be one or two or more, and can be attached to a desired position. By increasing the number of attached sensors, the state of filling of the foam from the start of the injection can be grasped quite precisely.

For example, the mold for molding the front seat for a vehicle is shown in FIG. 2, and this mold 11 is composed of a lower mold 12 and an upper mold 1 detachably connected to the lower mold 12.
3 and a core mold 14 disposed between the lower mold 12 and the upper mold 13. Then, the lower mold 12 and the upper mold 1
3 and the upper surface of the lower mold 12 and the core mold 1
4 and a large-capacity cavity 15 is formed between the lower surface of the upper die 13 and the upper surface on the tip side of the core die 14.
The partitioning projection 16 protruding from a required position on the upper surface of the core mold 14
A low-capacity cavity 17 is formed by this, and the large-capacity cavity 15 and the low-capacity cavity 17 communicate with each other via a gap 18 formed between the tip of the core mold 14 and one side wall of the lower mold 12. Has a large capacity cavity 15
On the other hand, the low-capacity cavities 17 are formed so as to be continuous in a state of being bent by approximately 180 °. In addition, the protrusion 1
A minute gap 19 is formed between the upper die 6 and the upper die 13.

The large and low capacity cavities 15,
The vehicle front seat 17 is formed such that the large-capacity cavity 15 forms a seat body serving as a front surface during mounting, and the low-capacity cavity 17 forms a mounting portion serving as a back surface during mounting. It is.

In such a mold, when a polyurethane foam is molded, a foaming stock solution is injected into a lower mold,
The upper mold is joined to the lower mold. The foaming starting solution starts foaming, fills the large-capacity cavity 15, and forms the gap 18.
When flowing into and filling the low-volume cavity 17 through the low-volume cavity 17, the gap 18 becomes narrow and the low-volume cavity 17
Is normally connected to the large-capacity cavity 15 so as to bend, so that when the foam passes through the gap 18 and flows into the low-capacity cavity 17 so as to flow further around, the flow form and the flow velocity of the foam are Vary considerably,
Gas accumulation or entrainment of air tends to cause defects. Therefore, at least any position corresponding to the large-capacity cavity 15 of the lower mold and the gap 1
Preferably, a fiber sensor is attached at a position corresponding to the low-capacity cavity of the upper mold and at a position corresponding to the low-capacity cavity, thereby observing the time required for the foam to pass through the gap 18 and the predetermined time of the low-capacity cavity. can do.

In the fluidity analysis of the present invention, a polyurethane foam material is supplied by a predetermined method into a mold to which the sensor 1 is attached, and the mold is closed by a predetermined method to detect data.

FIG. 3 is a conceptual diagram of the fluidity analysis method of the present invention. This mold 21 was equipped with a total of three fiber sensors 1, 1, 1 and was attached to the lower mold, and was attached to the beginning of the foam entering the low-capacity cavity of the upper mold. , Indicate those provided at the end of the foam.

Each of these fiber sensors 1, 1, 1 is connected to a fiber sensor pump unit 22, and the data sent thereto is sent to a data logger 24 and a monitor 25 through a sequencer unit 23, respectively. I have.

A thermocouple 26 (for measuring the temperature inside the foam) and a pressure sensor 27 (for measuring the foaming pressure) are mounted on the mold 21 at predetermined positions, and these are a thermocouple amplifier 28 and a pressure sensor, respectively. It is connected to the amplifier 29. Note that these connections are not essential in the present invention.

Each of the thermocouple amplifier 28 and the pressure sensor amplifier 29 is further connected to the data logger 24, so that the temperature and the temperature can be measured together with the data from the fiber sensor 1.
Pressure analysis can be performed.

Next, an embodiment of the present invention will be described with reference to FIG. First, the injection of the urethane foam material on the fiber sensor is started. (At this time, t = 0 seconds.) At the same time as t = 0, thermocouple 2
6. Observation of the temperature and pressure in the mold is simultaneously started by the pressure sensor 27, and the data is sent to the data logger 24 from the respective amplifiers 28 and 29.

The supplied material was molded by detecting that the foam grew with the progress of the reaction and that the foam passed in the order of the sensor and the sensor. At this time, each sensor transmits the data of the polyurethane foam to the data logger 24 and the monitor 2.
5 for analysis. When the sensor is ON, it is detected as a filter time.

From the above results, it is possible to observe the moving speed of the foam in the low-capacity cavity provided on the upper surface with the time difference between sensor ON and sensor ON.

In this case, the flow rate of the resin in the low-capacity cavity can be observed with the time difference from the sensor ON to the sensor ON, so that the flowability of the resin can be accurately measured.

According to the flowability analysis method of the present invention, the filter time is specified by detecting the direct flowability of the resin, so that the measurement can be performed accurately, and the timing of ejection from the vent hole as in the prior art can be determined. The accuracy is dramatically improved as compared with the case where.

[0030]

According to the flowability analysis method of the present invention, the flow state of a polyurethane foam having an open-cell structure or a closed-cell structure can be analyzed by a fiber sensor, and the molding is performed using a mold particularly suitable for mass production. It can be suitably adopted as a method for observing the flow state of a molded article.

[Brief description of the drawings]

FIGS. 1A and 1B are explanatory views of the structure of a fiber sensor, wherein FIG. 1A is a front view of the fiber sensor 1, and FIG.

FIG. 2 is a schematic sectional view showing an example of a mold used in the present invention.

FIG. 3 is a conceptual diagram of a method for analyzing the fluidity of a polyurethane foam according to the present invention.

[Explanation of symbols]

 1 Fiber sensor 21 Mold

Claims (2)

[Claims] A lower mold, an upper mold detachably disposed over an opening of the lower mold to form a sealed space between the lower mold, and a sealed space between the lower mold and the upper mold. Is provided with a through hole at a predetermined position of a mold as a cavity to which a material for a polyurethane foam molded article is supplied, and the through hole is filled with a transparent resin, and a fiber sensor is attached to the transparent resin filled portion. A method for analyzing the fluidity of a polyurethane foam, comprising supplying a polyurethane foam material into the mold, closing the mold, and then detecting data of the polyurethane foam material inside using the fiber sensor. 2. The method according to claim 1, wherein the mold includes a core die detachably disposed in the closed space, and when the core die is disposed, the upper surface of the core die and the lower surface of the upper die are separated. A low-capacity cavity is formed, and a large-capacity cavity is formed by the lower surface of the core mold and the upper surface of the lower die, and a cavity having a structure in which the low-capacity cavity and the large-capacity cavity are connected via a gap. The method for analyzing fluidity of a polyurethane foam according to claim 1, wherein