JP3442126B2 - Degradation degree prediction device and material physical property prediction device for thermally degraded resin - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CAE (CAD) system for designing processes, molds, materials, etc. by using a heat-degradable thermoplastic resin as a molding material, and more specifically,
The present invention relates to a deterioration degree prediction device and a material physical property prediction device for a heat-deteriorated resin, which enables examination of quality of a molded product before forming a molding process.

[0002]

2. Description of the Related Art Conventionally, a molding process simulation using a thermoplastic resin (see, for example, Japanese Patent Laid-Open No. 258252/1990).
No. 9) is proposed. This molding process simulation only obtains the changes in the physical quantity of the resin (pressure, temperature, viscosity, specific volume, etc.) during the injection molding process, making it difficult to evaluate the analysis results, that is, to feed it back to the product or mold design. Met.

Therefore, as a method of evaluating the filling analysis result in the injection process, Japanese Patent Laid-Open Nos. 1-67322 and 1- 1322 are available.
67323, JP-A-1-67320, JP-A1-1.
No. 23717, JP-A-1-123718, JP-A-1-
No. 123719 has been proposed. These things are
All of these are systems that search for optimum conditions for reducing the filling pressure, and it was not possible to evaluate the degree of deterioration of the resin related to the appearance and quality of the product.

Further, Japanese Unexamined Patent Publication No. 5-189526 discloses a technique for predicting a burn, which is a product quality, using a physical quantity (resin temperature) in a filling analysis.

For example, the flow analysis evaluation system for a mold for injection molding disclosed in Japanese Patent Laid-Open No. 189526/1993 discloses a gate dimension for preventing burnout which is a defective appearance that occurs during injection molding. A system for evaluation,
The resin flow rate, the gate diameter, and the number of gate points are used as the parameters to perform resin filling analysis, and the filling analysis unit that calculates the distribution of pressure, temperature, etc. While calculating the index value representing the burn for each gate score, based on the calculated index value for each parameter, the index calculation unit that finds a combination that achieves a value that allows for a safety factor from the burn limit, The display unit displays the relationship of each parameter that achieves each combination obtained by the index calculation unit in a graph for each number of gate points.

A second aspect of the present invention describes a system for evaluating a runner dimension in which the gate diameter and the number of gate points described in the first aspect are replaced by a runner length, a runner diameter, and the number of runners.

The system for predicting burns, which is shown in the prior art, evaluates the presence or absence of burns based on the instantaneous temperature (maximum temperature during molding) in the filling process. Hereinafter, this technique will be referred to as Conventional Technique 1.

[0008]

By the way, the heat-degradable resin has a characteristic that it deteriorates when left in the temperature field for a long time even at a low temperature. Therefore, the conventional technique 1 described above can be applied to a very short time process (for example, a filling process), but a relatively long time process (for example, a screw mold or a hot runner mold). There was a problem that it could not be applied to the prediction of the occurrence of burns in the flow process of (1).

Further, the above-mentioned prior art 1 only evaluates the occurrence of burns, and cannot evaluate the degree of deterioration of the resin when burns have not occurred. Therefore, there is a problem that evaluation of process stability against burns and evaluation of physical properties (product strength) accompanying deterioration cannot be performed.

The present invention was devised to solve such problems, and its purpose is to be applicable to all processes and to quantitatively evaluate the degree of deterioration of heat-degradable resin and the physical properties of materials. Deterioration degree prediction device and material properties prediction
To provide a measuring device .

[0011]

In order to solve the above problems, a deterioration degree prediction device for a heat deterioration resin according to claim 1 of the present invention is a molding process simulation for evaluating a mold structure, molding conditions, molding materials and the like. In, in the thermal characteristics data of the resin as an input data, the thermal deterioration characteristics approximate expression calculation means for calculating an approximate expression using the time change of the thermal deterioration degree as a function of temperature, and the analysis of molding condition data, resin physical property data, etc. Using various necessary data as input data, at least the temperature change of the molding material during the molding process is calculated, and the heat history calculation means for calculating the temperature of the resin at each time based on the calculation result, and the heat deterioration characteristic approximation formula A heat deterioration calculator for calculating the degree of heat deterioration of a molded article by using the approximate expression calculated by the calculation means and each data of the heat history calculated by the heat history calculation means as input data. A structure with a door.

The material physical property predicting apparatus according to claim 2 of the present invention uses the thermal characteristic data of the resin as input data in the molding process simulation for evaluating the mold structure, molding conditions, molding material, etc. As a heat deterioration characteristic approximation formula calculating means for calculating an approximation formula using the time change of as a function of temperature, and an approximation formula calculated by this heat deterioration characteristic approximation formula calculating means and thermal property data of resin physical properties as input data, A resin physical property approximate expression calculating means for calculating an approximate expression in which the resin physical property is a function of the thermal deterioration degree, and various data necessary for analysis of molding condition data, resin physical property data, etc. as input data, At least the temperature change is calculated, and the thermal history calculation means for calculating the temperature of the resin at each time based on the calculation result and the resin physical property approximate expression calculation means are calculated. Each data thermal history calculated by the approximate expression and the thermal history calculation means as input data, a configuration in which a physical property calculation means for calculating the resin properties of the molded article.

[0013]

[Function] The reason why the degree of heat deterioration of the resin cannot be quantitatively evaluated is that the heat deterioration characteristic of the resin is not quantitatively measured (not formulated) and the heat history of the resin in the molding process is considered. There are two points of not being.

[0014] Therefore, it illustrates a representative method of measuring the thermal degradation properties of the resin below. By these methods, it is possible to measure and formulate the physical properties of the thermal deterioration degree.

[0015] (1) Color difference method thermally degradable resin, as seen as a scorch phenomenon will be colored by heat load. However, by visual inspection or the like, this burn-off phenomenon can only be judged as a distinctly colored state or an uncolored state.

[0016] Therefore, in the present invention, the thermal load device gear oven or the like, the thermal load temperature and time known sample (the sample resin is early it is desirable color is white.) To prepare, its The color saturation of the sample is measured by a color difference meter or the like. This makes it possible to quantitatively grasp the color change (degree of deterioration) of the uncolored region of the sample by visual observation. An example of the measurement result by this method is shown in FIG.

[0017] (2) dehydrochlorination process thermal degradation of particularly intense vinyl chloride resin has a structure as shown in FIG. Then, when a certain amount of heat load is applied, the structure changes to a structure (a structure in which hydrogen ions and chlorine ions are bonded and separated) as shown in FIG. 4, causing coloring and deterioration, which causes poor appearance and poor strength. Is generally known.

In other words, it can be seen that the more deteriorated the resin, the lower the chlorine content. Therefore, similar to the color difference method, a sample with a known heat load temperature and time is prepared, and the amount of chlorine (correctly, amount of hydrogen chloride) contained in the sample is measured to quantitatively grasp the degree of deterioration. can do.

[0019] (3) As shown in the double bond method Figure 3 and Figure 4, the thermal degradation of particularly intense vinyl chloride-based resin, the number of double bonds the deterioration proceeds is increased. Therefore, the degree of deterioration can be quantitatively grasped by producing a sample in which the heat load temperature and time are known in the same manner as described above and measuring the number of double bonds contained in the sample.

Next, a description will be given of the operation of the invention described in claim 1.

In the molding process simulation for evaluating the mold structure, molding conditions, molding material, etc., the thermal deterioration characteristic approximation formula calculation means inputs the thermal characteristic data of the resin (degradation degree substitute value, temperature, time, etc.). As data, an approximate expression in which the temporal change of the thermal deterioration degree is used as a function of temperature is calculated. This makes it possible to formulate the degree of thermal deterioration as a function of temperature and time.

The heat history calculation means uses various data necessary for analysis of molding condition data, resin physical property data, etc. as input data, and uses a numerical analysis method including a finite element method, a difference method, a boundary element method, a FAN method, etc. Calculate the physical behavior changes (pressure, temperature, density, etc.) of the molding material during the molding process. In the present invention, at least the temperature change is calculated in a stationary state. Then, the temperature of the resin at each time is calculated based on the calculation result. That is, the thermal history in the molding process is calculated by outputting the calculated temperature at each time to the temperature history storage device.

The heat deterioration calculating means uses the heat deterioration characteristic approximate expression calculated by the heat deterioration characteristic approximate expression calculating means and the heat history data calculated by the heat history calculating means as input data to determine the heat deterioration degree of the resin. calculate.

[0024] The description of the operation of the invention described in claim 2.

In the molding process simulation for evaluating the mold structure, molding conditions, molding material, etc., the thermal deterioration characteristic approximate expression calculating means inputs the thermal characteristic data of the resin (degradation degree substitute value, temperature, time, etc.). As data, an approximate expression in which the temporal change of the thermal deterioration degree is used as a function of temperature is calculated. This makes it possible to formulate the degree of thermal deterioration as a function of temperature and time.

The resin physical property approximate expression calculating means uses the thermal deterioration characteristic approximate expression calculated by the thermal deterioration characteristic approximate expression calculating means and the thermal property data of the resin physical property as input data, and the resin physical property as a function of the thermal deterioration degree. Calculate an approximate expression. The resin that has undergone heat deterioration has reduced mechanical properties such as rigidity and impact properties, and therefore product quality is degraded. Therefore, the resin physical properties of the sample with a known heat load are measured, but the sample with a known heat load can be converted into the degree of heat deterioration (alternative property) as described in the heat deterioration characteristic approximation formula calculation means. The physical properties of the resin can be formulated by an approximate expression as a function of the degree of thermal deterioration.

In the heat history calculating means, various data necessary for analysis of molding condition data, resin physical property data, etc. are used as input data, and numerical analysis methods including finite element method, difference method, boundary element method, FAN method, etc. are used. Calculate the physical behavior changes (pressure, temperature, density, etc.) of the molding material during the molding process. In the present invention, at least the temperature change is calculated in a stationary state. Then, the temperature of the resin at each time is calculated based on the calculation result. That is, the thermal history in the molding process is calculated by outputting the calculated temperature at each time to the temperature history storage device.

The physical property calculating means calculates the resin physical properties of the molded product by using as input data the respective data of the thermal deterioration characteristic approximate expression calculated by the resin physical property approximate expression calculating means and the thermal history calculated by the thermal history calculating means. .

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

[0030] Figure 1 shows an electrical configuration of the deterioration degree prediction device engaging Waru heat degradation resin and material property prediction apparatus according to the present invention.

The prediction apparatus of the present invention, heat aging characteristics approximate expression calculation apparatus 1, the physical properties of the resin approximate expression calculation unit 2 is constituted by a thermal history calculating unit 3 and thermal degradation / properties calculation unit 4.

The heat deterioration characteristic approximation formula calculation device 1 calculates an approximation formula in which the temporal change of the heat deterioration degree is used as a function of temperature, and the heat characteristic data of the resin is given as input data. This thermal characteristic data is data such as a deterioration degree substitute value, temperature, and time.

The output of the thermal degradation properties approximate expression calculation device 1 is guided to the resin properties approximate expression calculating unit 2 and the thermal degradation / properties calculation unit 4.

The resin physical property approximate expression calculating device 2 uses the thermal deterioration characteristic approximate expression calculated by the thermal deterioration characteristic approximate expression calculating device 1 and the thermal property data of the resin physical property as input data.
This is a block for calculating an approximate expression in which the resin physical properties are a function of the thermal deterioration degree, and the output thereof is guided to the thermal deterioration / physical property calculation device 4. Thermal property data of resin physical properties are Young's modulus,
It is data such as Poisson's ratio, linear expansion coefficient, impact strength, yield stress, strain hardening coefficient, viscosity, and thermal conductivity.

On the other hand, the thermal history calculating unit 3, the molding condition data, as input data to various kinds of data necessary for the analysis of such resin properties data, finite element method, finite difference method, boundary element method, FA
This is a block for calculating at least the temperature change of the molding material during the molding process in a non-steady state by a numerical analysis method including the N method and calculating the temperature (heat history) of the resin at each time based on the calculation result. This calculated thermal history data is
It is guided to the heat deterioration / physical property calculation device 4.

The heat deterioration / physical property calculation device 4 uses, as input data, each data of the heat deterioration characteristic approximation formula calculated by the heat deterioration characteristic approximation formula calculation device 1 and the heat history calculated by the heat history calculation device 3. Calculate the degree of heat deterioration of the resin. Further, the thermal deterioration / physical property calculation device 4 uses the respective data of the resin physical property approximate expression calculated by the resin physical property approximate expression calculation device 2 and the heat history calculated by the heat history calculation device 3 as input data, and calculates This is a block for calculating the physical properties of the resin.

Next, the operation of the prediction apparatus of the above configuration.

The heat characteristic data (heat deterioration characteristic data) input to the heat deterioration characteristic approximate expression calculating device 1 is measured by a resin heat deterioration characteristic measuring method such as the color difference method, the dehydrochlorination method or the double bond method described above. . In this example, the color difference method was used for the measurement. The measurement result is shown in FIG. FIG. 2 shows characteristic data of a vinyl chloride resin, and this data is peculiar to the resin.

In the heat deterioration characteristic approximation formula calculation device 1, the heat deterioration characteristic approximation formula shown in the following formula (1) is obtained based on this characteristic data. In this embodiment, the approximation formula used is the Arrhenius type formula that is the best approximation to the resin.

[0040]

[Equation 1]

[0041] However, f: the degree of thermal degradation, T: temperature, t: time, A, B: constants The thermal degradation characteristic approximate expression data, the resin properties approximate expression calculating unit 2 and the thermal degradation / properties calculation device 4 Given to.

Further , the resin physical property approximate expression calculating device 2 is provided with a plurality of types (at least three types or more) of samples having known thermal loads or thermal degradation degrees (for example, samples for measuring thermal degradation characteristics used in the color difference method). ) Physical properties (Young's modulus, Poisson's ratio, linear expansion coefficient, etc.) are measured. Resin that has undergone heat deterioration has reduced mechanical properties such as rigidity and impact,
Product quality deteriorates. Therefore, the resin physical properties of the sample with a known heat load are measured. For the sample with a known heat load, the degree of heat deterioration (alternative property) is described as described in the processing by the heat deterioration characteristic approximation formula calculation device 1. Since it can be converted into, the physical properties of the resin can be formulated by an approximate expression as a function of the degree of thermal deterioration.

[0043] That is, the resin properties approximate expression calculating apparatus 2, the resin properties data (in this embodiment of the thermal degradation properties approximate expression and resin properties calculated by the thermal degradation properties approximate expression calculation apparatus 1, and the Young's modulus only .) As input data, a resin physical property approximation formula represented by the following formula (2) expressing the resin physical property as a function of the degree of thermal deterioration is calculated.

[0044]

[Equation 2]

[0045] However, A, B, C, D: constant The resin properties characteristic approximate expression data is provided to heat degradation / properties calculation unit 4.

Meanwhile, the thermal history calculating unit 3, the molding condition data, product model (analysis model), as input data to various kinds of data necessary for the analysis of such resin properties data, finite element method, finite difference method, boundary element method, The physical behavior change (pressure, temperature, density, etc.) of the resin during the molding process is calculated by a numerical analysis method including the FAN method and the like.

In this embodiment, a model having a shape shown in FIG. 5 is used as an analytical model, and this model is simulated under the respective molding conditions of condition a and condition b shown in FIG. History) is calculated. The shape model shown in FIG. 5 is the simplest flat plate model, and has a configuration in which gates are provided at two positions on the left and right.

[0048] An example of a thermal history obtained at this time is shown in FIG. This thermal history data is given to the thermal deterioration / physical property calculation device 4.

The heat deterioration / physical property calculation device 4 uses the heat deterioration characteristic approximation formula [Equation (1)] calculated by the heat deterioration characteristic approximation formula calculation device 1 and the heat history calculated by the heat history calculation device 3 (see FIG. Based on each data of 7), the thermal deterioration degree of the resin is calculated by the following formula (3), and the resin physical property approximate formula calculated by the resin physical property approximate formula calculating device 2 [Formula (2)]
The resin physical properties (Young's modulus in this example) of the molded product are calculated by substituting the thermal deterioration degree obtained by the equation (3) into

[0050]

[Equation 3]

[0051] Each molding conditions shown in FIG. 6 a, the degree of thermal degradation and the Young's modulus in the case of molding by b shown in FIG.

[0052] In this case, for the degree of thermal degradation, its value is 2
If it is 2.0 or more, burns occur, which is a problem in appearance quality. Therefore, this value (22.0) is set as the burn limit value (reference deterioration degree value). In addition, regarding the physical properties of the resin, when the value (Young's modulus) is 1.00 or less, poor physical properties occur. Therefore, this value (1.00) is set as the physical property limit value.

From FIG . 8, it is predicted that under the condition a, the degree of thermal deterioration is larger than the burn-off limit value of 22.0, a burn-in defect that causes a problem in appearance occurs, and the physical properties are significantly reduced. Therefore, in this case, design change is necessary.

Further , under the condition b, there is no occurrence of a burn that causes a problem in appearance, but since it is at the limit, it is possible to determine that a burn may occur due to a slight variation in molding conditions on site.

[0055]

EFFECT OF THE INVENTION Deterioration degree predicting apparatus for heat-deteriorating resin of the present invention
Is a heat deterioration that calculates an approximate expression that uses the thermal characteristic data of the resin as input data in a molding process simulation that evaluates the mold structure, molding conditions, molding materials, etc. Using the characteristic approximation formula calculating means and various data necessary for analysis of molding condition data, resin physical property data, etc. as input data, at least the temperature change of the molding material during the molding process is calculated, and based on this calculation result, each resin of the resin is calculated. A heat history calculation means for calculating the temperature of time, an approximation formula calculated by the heat deterioration characteristic approximation formula calculation means, and each data of the heat history calculated by the heat history calculation means are used as input data, and the heat deterioration degree of the molded article is calculated. than was configured to include the thermal degradation calculating means for calculating a are those capable of performing predictive evaluation of the degree of deterioration of the molded article.

[0056] Also, thermal degradation resin material property prediction of the present invention
In the molding process simulation that evaluates the mold structure, molding conditions, molding materials, etc. , the equipment uses the thermal characteristic data of the resin as input data to calculate an approximate expression that uses the time change of the thermal deterioration degree as a function of temperature. Degradation characteristic approximate expression calculating means, and a resin for calculating an approximation expression using the resin physical properties as a function of the degree of thermal deterioration by using the approximation expression calculated by the thermal deterioration characteristic approximate expression calculating means and the thermal characteristic data of the resin physical properties as input data. Physical property approximation formula calculation means, molding condition data, various data required for analysis of resin physical property data, etc. are used as input data to calculate at least the temperature change of the molding material during the molding process, and based on this calculation result, each resin The heat history calculating means for calculating the temperature of time, the approximation formula calculated by the resin physical property approximate expression calculating means, and the respective heat history data calculated by the heat history calculating means. The data as input data, a structure in which a physical property calculation means for calculating the resin properties of the molded article
And the in, but capable of performing predictive evaluation of the physical properties of the molded article.
In addition, since it is possible to perform such a predictive evaluation of the degree of deterioration of the molded product and a predictive evaluation of the physical properties of the molded product, it becomes possible to examine the quality of the molded product before manufacturing the molding process, and to change the structure and conditions during process development. This has the effect of reducing the time loss and cost loss that accompany it.

[Brief description of drawings]

1 is a block diagram showing an electrical configuration of the present invention the degradation degree prediction device engaging Waru heat degradation resin <br/> and material property prediction device.

FIG. 2 is characteristic data of vinyl chloride resin measured by a color difference method.

FIG. 3 shows the chemical structure of a vinyl chloride resin.

FIG. 4 shows a structure in which a hydrogen ion and a chlorine ion are bonded and separated from the chemical structure shown in FIG.

FIG. 5 is a diagram showing an example of an analysis model.

FIG. 6 is a table showing molding conditions.

7 is a diagram showing an example of a heat history when simulated under the molding conditions shown in FIG.

8 is a table showing the degree of thermal deterioration and Young's modulus when molded under the forming conditions shown in FIG.

[Explanation of symbols]

1 Thermal deterioration characteristic approximation formula calculation device 2 Approximate calculation system for resin physical properties 3 Heat history calculator 4 Thermal deterioration / physical property calculator

Claims (2)

(57) [Claims] 1. In a molding process simulation for evaluating a mold structure, molding conditions, molding materials, etc., an approximate expression is calculated with a thermal characteristic data of a resin as input data and a temporal change of a thermal deterioration degree as a function of temperature. Using the heat deterioration characteristic approximation formula calculation means and various data necessary for analysis of molding condition data, resin physical property data, etc. as input data, calculate at least the temperature change of the molding material during the molding process, and based on this calculation result A heat history calculating means for calculating the temperature of the resin at each time, each of the data of the heat history calculated by the heat history calculating means and the approximate expression calculated by the heat deterioration characteristic approximate expression calculating means is used as the input data. A deterioration degree prediction device for a heat deterioration resin, comprising: a heat deterioration calculation means for calculating a heat deterioration degree of a product. 2. In a molding process simulation for evaluating a mold structure, molding conditions, molding materials, etc., an approximate expression is calculated by using a thermal characteristic data of a resin as input data and using a temporal change of a thermal deterioration degree as a function of temperature. Heat deterioration characteristic approximation formula calculating means, and the approximation formula calculated by the heat deterioration characteristic approximation formula calculating means and the heat characteristic data of the resin physical properties as input data, and the approximation formula using the resin physical properties as a function of the heat deterioration degree is calculated. Using at least the resin physical property approximate expression calculation means and various data necessary for analysis of molding condition data, resin physical property data, etc. as input data, calculate at least the temperature change of the molding material during the molding process, and based on this calculation result Of the heat history calculating means for calculating the temperature of each time, the approximate expression calculated by the resin physical property approximate expression calculating means and the heat calculated by the heat history calculating means A material physical property prediction apparatus comprising: a physical property calculating unit that calculates a resin physical property of a molded product by using each data of history as input data.