JP6804682B1 - How to evaluate the squeaking noise of resin molded products - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for evaluating the degree of squeaking noise generated when resin molded products are dynamically contacted with each other.
SOLUTION: The surface free energy on the surface of the resin molded products 10 and 20 and the polar component and the dispersion component of the surface free energy are obtained by the Owns and Wend method, and then squeaks by each value of the polar parameter and the surface free energy. Evaluate the sound.
[Selection diagram] None

Description

The present invention relates to a method for evaluating the degree of squeaking noise generated when resin molded products are dynamically contacted with each other.

Conventionally, molded products made of resin compositions have been widely used in the fields of vehicles, OA (office automation) equipment, precision equipment, household electrical equipment, furniture, daily necessities, toys, etc. by taking advantage of various characteristics. In the constituent members and the like used in these fields, for example, the resin molded product made of the resin composition X and the resin molded product made of the same or different material as the resin composition X are in contact with each other or are in contact with each other. It may have structures arranged at predetermined intervals. In particular, when resin molded products are in contact with each other, one or both of them move or deform due to vibration, rotation, twisting, sliding, impact, etc. and dynamically contact each other, resulting in an unpleasant squeaking noise (rubbing noise). It is known to occur. For example, an air conditioner or audio housing component arranged in an automobile and a fitting component arranged on the periphery thereof strongly rub against each other due to vibration or the like to generate an unpleasant sound. This squeaking sound is a sound caused by the stick-slip phenomenon that occurs when two objects rub against each other, and is said to be different from the slidability between the objects.

In recent years, resin parts (automobile interior parts, office equipment, housing interior parts, etc.) with measures against squeaking noise are widely known. For example, Patent Document 1 describes ethylene / α having a melting point of 0 ° C. or higher. It is composed of a rubber-reinforced vinyl resin obtained by polymerizing a vinyl monomer in the presence of an olefin rubber polymer and a thermoplastic resin composition containing a polycarbonate resin, and is an ethylene / α-olefin resin. A contact component in which the content of the rubbery polymer is 5 to 30% by mass with respect to 100% by mass of the thermoplastic resin composition is disclosed.

Japanese Unexamined Patent Publication No. 2012-46669

For example, when a composite having a structure in which a plurality of resin molded products are in contact with each other receives vibration, rotation, twisting, sliding, impact, etc., or when they are in a non-contact state with each other, vibration, rotation, twisting, sliding. The degree of squeaking noise generated when one resin molded product or both resin molded products move or deform due to impact, etc. and dynamically contact each other. If it can be predicted, it is possible to easily select a molding material suitable for the application for which squeaking noise is desired to be suppressed. An object of the present invention is to provide a method for evaluating the degree of squeaking noise generated when resin molded products are dynamically contacted with each other.

The present inventors have made resin molded products from each other from the surface free energy γ on the surface of the resin molded product, the polar component γ ^p and the dispersion component γ ^d of the surface free energy γ, and the polar parameter S obtained from these. We have found that it is possible to evaluate the degree of squeaking that occurs when contact is made dynamically.
The present invention is shown below.
1. 1. It is a method to evaluate the degree of squeaking noise generated when resin molded products dynamically contact each other.
The surface free energy γ on the surface of the resin molded product, the polar component γ ^p and the dispersion component γ ^d of the surface free energy γ are obtained by the Owns and Wend method, and then the polar parameters S and the polar parameters S calculated by the following formula are obtained. A squeaking sound evaluation method, characterized in that the squeaking sound is evaluated by each value of the surface free energy γ.
S = γ ^p / γ = γ ^p / (γ ^p + γ ^d )
2. 2. The squeaking sound evaluation method according to Item 1, wherein it is determined that squeaking noise is unlikely to occur when the surface free energy γ is 50 mJ / m ² or less and the polarity parameter S is 0.2 or less.
3. 3. A resin molded product evaluated by the squeaking sound evaluation method according to the above item 1 or 2, characterized in that the surface free energy γ is 50 mJ / m ² or less and the polarity parameter S is 0.2 or less. A resin molded product that does not easily squeak.

According to the squeaking noise evaluation method of the present invention, it is possible to grasp the degree of squeaking noise generated when the resin molded products dynamically contact each other. For example, when a composite having a structure in which a plurality of resin molded products are in contact with each other receives vibration, rotation, twisting, sliding, impact, etc., or when they are in a non-contact state with each other, vibration, rotation, twisting, sliding. The degree of squeaking noise generated when one resin molded product or both resin molded products move or deform due to impact, etc. and dynamically contact each other. Can be predicted, so that the molding material of the resin molded product can be accurately selected according to the application. When a plurality of resin molded products in the case where the surface free energy γ is 50 mJ / m ² or less and the polarity parameter S is 0.2 or less are used, squeaking noise is unlikely to occur. It is suitable for applications such as vehicles, ships, aviation, OA equipment, household electrical equipment, electric / electronic equipment, building materials, daily miscellaneous goods, sports, and stationery.

It is sectional drawing which shows the structural example of two resin molded articles which may generate a squeaking noise at the time of dynamic contact.

Hereinafter, the present invention will be described in detail. In addition, in this specification, "(co) polymer" means a homopolymer and a copolymer.

In the evaluation method of the present invention, for example, as shown in FIG. 1, in a composite body in which two resin molded products 10 and 20 are combined, one or both of them move or deform dynamically due to vibration, twist, impact, etc. This is a method for determining the degree of squeaking noise generated when contact (surface contact, line contact, or point contact) occurs.
FIG. 1 (1) shows a mode in which the member 10 of 1 and the other member 20 are adjacent to each other. In (2) and (3), the member 10 of 1 is fitted into a recess formed in the other member 20. (4) is a mode in which the other member 20 is fitted into the recess formed in the member 10. (5) is an embodiment in which another member 20 is arranged so as to be in close contact with the inner wall surface of the tubular member 10. Further, (6) is an embodiment in which one member 10 and another member 20 are arranged with a predetermined gap.

In the evaluation method of the present invention, first, the surface free energy γ on the surface of the resin molded product and the polar component γ ^p and the dispersion component γ ^d of the surface free energy γ are obtained by the Owns and Wendt method.
Here, the surface free energy is the energy that a molecule on a solid or liquid surface has extra energy as compared with a molecule inside a substance. In the present invention, the surface free energy γ of the resin molded product refers to the surface free energy at 23 ° C. ± 3 ° C. The surface free energy γ can be obtained by a known method, but in the present invention, it is obtained by the Owns and Wendt method. The polar component γ ^p and the dispersion component γ ^{d of the} surface free energy γ are also obtained by the same method.

The Owns and Wend method is described in the literature (J. Appl. Polymer. Sci., 13, 1741-1747 (1969)), and a liquid having a known surface free energy (test liquid) on the surface of a resin molded product. Is dropped, the contact angle θ is measured, and the surface free energy γ and its polar component γ ^p and dispersion component γ ^d are calculated from the following formulas (I), (II) and (III). In addition, θ is the contact angle in the test liquid, γ ^d is the non-polar component of the surface free energy γ of the surface of the resin molded product, γ _L ^d is the non-polar component of the surface free energy of the test liquid, and γ ^p is. polar component of the surface free energy gamma of the resin molded article surface, gamma _L ^p is the polar component of the surface free energy of the test fluid.
(1 + cos θ) ・ γ _L / 2 = [(γ ^d・ γ _L ^d )] ^1/2 + [(γ ^p・ γ _L ^p )] ^1/2 (I)
γ = γ ^d + γ ^p (II)
γ _L = γ _L ^d + γ _L ^p (III)

In the present invention, it is preferable to use water and diiodomethane (methylene iodide) as the test liquid. Polar component gamma _L ^p and variance component gamma _L ^d of the surface free energy gamma of water, respectively, was 51.0mJ / ^{m 2} and 21.8mJ / ^{m 2,} the polar component of the surface free energy gamma diiodomethane gamma _L ^p And the dispersion component γ _L ^d is 1.3 mJ / m ² and 49.5 mJ / m ² , respectively. By introducing these values and the values of the contact angle θ using each test liquid into the above formulas (I) to (III), the surface free energy γ of the surface of the resin molded product, its polar component γ ^p, and its polar component γ ^p and The dispersion component γ ^d can be calculated.

After obtaining the surface free energy γ on the surface of the resin molded product and the polar component γ ^p and the dispersion component γ ^d of the surface free energy γ as described above, the polar parameter S is obtained by the following formula (IV). ..
S = γ ^p / γ = γ ^p / (γ ^p + γ ^d ) (IV)

The present invention evaluates the squeaking sound by each value of the polarity parameter S and the surface free energy γ. The squeaking noise has (1) the upper limit of the surface free energy γ is 50 mJ / m ² and the upper limit of the polar parameter S is 0.2, and (2) the upper limit of the surface free energy γ is 48 mJ / m ² and the upper limit of the polar parameter S is. 0.15, (3) The upper limit of the surface free energy γ is 46 mJ / m ² and the upper limit of the polar parameter S is 0.1, (4) The upper limit of the surface free energy γ is 44 mJ / m ² and the upper limit of the polar parameter S is It becomes less likely to occur in the order of 0.06. The ability to be evaluated in this way is useful as a method for evaluating squeaking noise because it has a correlation with the evaluation result based on the abnormal noise risk value by a known stick slip test.

The resin molded product according to the present invention may consist of either a thermoplastic resin composition or a cured resin composition, but is preferably composed of a thermoplastic resin composition.
Examples of the thermoplastic resin contained in the thermoplastic resin composition include ABS resin, AES resin, ASA resin, acrylic resin, polycarbonate resin, polyamide resin, polyolefin resin, polyester resin, polyarylate resin, and vinyl-based (co) polymer (co) polymer. Aromatic vinyl (co) polymer, polyvinyl chloride resin, polyvinylidene chloride resin, fluororesin, etc.), polyethylene glycol resin, ethylene copolymer as the main chain, and aromatic vinyl (co) polymer side Examples thereof include a graft resin having a chain as a main chain and a graft resin having an aromatic vinyl-based (co) polymer as a side chain with polyolefin as the main chain. These thermoplastic resins may be used alone or in combination of two or more.
The thermoplastic resin composition may contain an additive. These additives include fillers, plasticizers, antioxidants, UV absorbers, antioxidants, flame retardants, stabilizers, weathering agents, light stabilizers, heat stabilizers, antistatic agents, water repellents, and repellents. Examples include oil agents, antibacterial agents, preservatives, colorants (pigments, dyes, etc.).

When the resin molded product according to the present invention is made of a thermoplastic resin composition, it may be obtained by any molding method. Examples of the molding method include injection molding, extrusion molding, deformed extrusion molding, hollow molding, compression molding, vacuum molding, foam molding, blow molding, injection compression molding, gas assist molding, water assist molding and the like. Further, even in a composite in which a film containing the thermoplastic resin is bonded to the surface of a base made of a material other than the above, the method for evaluating squeaking noise can be applied to the surface of the film.

Next, the present invention will be described in more detail with reference to experimental examples using the thermoplastic resin composition. In the following, parts and% are based on mass unless otherwise specified.

1. 1. Raw material components The resins used in the following experimental examples are as follows.
(1) PMMA resin: "Parapet G" manufactured by Kuraray (trade name)
(2) ABS resin: "ABS150" manufactured by Techno-UMG (trade name)
(3) Polyamide resin: "A1030BRL" manufactured by Unitika Ltd. (trade name)
(4) EGMA-AS graft resin: "Modiper A4400" manufactured by NOF CORPORATION (trade name)
(5) PC resin: "Novalex 7022R" manufactured by Mitsubishi Engineering Plastics (trade name)
(6) PEG resin: "PEG-20000" manufactured by Sanyo Chemical Industries, Ltd. (trade name)
(7) PP resin: "Novatec PP BC03C" manufactured by Japan Polypropylene Corporation (trade name)
(8) PP-AS graft resin: "Modiper A3400" manufactured by NOF CORPORATION (trade name)
(9) PE resin: "Novatec LD LJ802" manufactured by Japan Polyethylene Corporation (trade name)
(10) PE-AS graft resin: "Modiper A1401" manufactured by NOF CORPORATION (trade name)
(11) Antioxidant: "ADEKA STAB PEP-36" manufactured by ADEKA (trade name)

2. 2. Preparation of thermoplastic resin test piece and evaluation of squeaking noise A test piece was prepared using the above raw materials, and a droplet of water or diiodomethane was dropped on the surface of the test piece to measure the contact angle. Then, the surface free energy γ and the polarity parameter S were obtained by the above-mentioned Owns and Wendt method. In addition, the prepared test piece was separately subjected to a stick slip test to obtain an abnormal noise risk value.

Experimental Example 1
Pellets made of PMMA resin and ABS resin as thermoplastic resin components are used in an injection molding machine "IS-170FA" (model name) manufactured by Toshiba Machine Co., Ltd., and have a cylinder temperature of 250 ° C., an injection pressure of 50 MPa, and a mold temperature of 60 ° C. A molded product having a length of 150 mm, a width of 100 mm, and a thickness of 4 mm was obtained by injection molding. This molded body is cut with a disc saw, the edges are chamfered with sandpaper with a count of # 100, and fine burrs are removed with a cutter knife to measure the contact angle (length 50 mm, width 30 mm, thickness). 4 mm), and test pieces X (length 60 mm, width 100 mm, thickness 4 mm) and Y (length 50 mm, width 25 mm, thickness 4 mm) for stick slip test were obtained. After that, the following measurements were performed and the results are shown in Table 1.

(1) Measurement of contact angle After adjusting the state of the contact angle measurement test piece under the conditions of temperature 23 ° C. and humidity 50% RH for 48 hours, Kyowa Interface Science Co., Ltd. contact angle meter "Dropmaster DMo501" (trade name). ) Was used to measure the contact angle with water and diiodomethane by the sessile drop method. The measurement conditions of the sessile drop method were a droplet volume of 2 μL, measurement 1 second after landing, an environmental temperature of 23 ° C. ± 3 ° C., and an environmental humidity of 50% ± 10%. The contact angle of water was 74 degrees and the contact angle of diiodomethane was 48 degrees. From these results, the surface free energy γ = 39.1 mJ / m ² and the polarity parameter S = 0.21 were obtained based on the Owns and Wendt method.

(2) Stick-slip test After adjusting the state of the stick-slip test test pieces X and Y under the conditions of temperature 23 ° C. and humidity 50% RH for 48 hours, the stick-slip tester “SSP-02” manufactured by ZIEGLER Co., Ltd. (Model name), and the conditions with the highest risk of abnormal noise when these test pieces are rubbed three times at a temperature of 23 ° C, humidity of 50% RH, load of 40 N, speed of 1 mm / sec, and amplitude of 20 mm. When the numerical value of was extracted, it was 10. This was used as the abnormal noise risk value in this example. The higher the abnormal noise risk value, the higher the risk of squeaking.

Experimental Examples 2-4
The same operation and evaluation as in Experimental Example 1 were carried out except that the amounts of PMMA resin and ABS resin used were changed so that the contact angles with water and diiodomethane were different. The results are shown in Table 1.

Experimental Example 5
The same operations and evaluations as in Experimental Example 1 were performed except that a polyamide resin and an ABS resin were used as the thermoplastic resin components. The results are shown in Table 1.

Experimental Example 6
The same operations and evaluations as in Experimental Example 1 were performed except that the polyamide resin, EGMA-AS graft resin, and ABS resin were used as the thermoplastic resin components. The results are shown in Table 1.

Experimental Examples 7 and 8
The same operations and evaluations as in Experimental Example 6 were carried out except that the amounts of the polyamide resin, EGMA-AS graft resin and ABS resin used were changed so that the contact angles with respect to water and diiodomethane were different. The results are shown in Table 1.

Experimental Example 9
The same operations and evaluations as in Experimental Example 1 were performed except that a PC resin, a PEG resin, a PP resin, and a PP-AS graft resin were used as the thermoplastic resin components. The results are shown in Table 1.

Experimental Examples 10 and 11
The same operation and evaluation as in Experimental Example 9 were carried out except that the amounts of the PC resin, PEG resin, PP resin and PP-AS graft resin used were changed to make the contact angles with water and diiodomethane different. The results are shown in Table 1.

Experimental Example 12
The same operations and evaluations as in Experimental Example 1 were performed except that a PC resin, a PP resin, and a PP-AS graft resin were used as the thermoplastic resin components. The results are shown in Table 1.

Experimental Example 13
The same operations and evaluations as in Experimental Example 1 were performed except that PC resin and ABS resin were used as the thermoplastic resin components. The results are shown in Table 1.

Experimental Example 14
The same operations and evaluations as in Experimental Example 1 were performed except that a PC resin, an ABS resin, a PE resin, and a PE-AS graft resin were used as the thermoplastic resin components. The results are shown in Table 1.

Experimental Example 15
The same operations and evaluations as in Experimental Example 14 were carried out except that the amounts of the PC resin, ABS resin, PE resin and PE-AS graft resin used were changed to make the contact angles with water and diiodomethane different. The results are shown in Table 1.

From Table 1, when the surface free energy γ is 50 mJ / m ² or less and the polarity parameter S is 0.2 or less, squeaking noise is unlikely to occur, and in particular, the surface free energy γ is 46 mJ / m ² or less. It can be seen that when the polarity parameter S is 0.1 or less, the risk of squeaking noise is further reduced. Therefore, by obtaining the surface free energy γ on the surface of the resin molded product, it was possible to easily determine whether or not a squeaking noise is likely to occur.

According to the squeaking sound evaluation method of the present invention, when a plurality of resin molded products are arranged in contact with each other or at predetermined intervals and used in applications such as vibration, rotation, twisting, sliding, impact, etc. It is possible to efficiently determine whether or not the resin molded product generates a squeaking noise. The resin molded product of the present invention is suitable as a member constituting a vehicle, an OA device, a household electric device, an electric / electronic device or a building material, a ship, daily necessities, a sporting goods, a stationery or the like.

10: Resin molded product, 20: Resin molded product

Claims (2)

It is a method to evaluate the degree of squeaking noise generated when resin molded products dynamically contact each other.
The surface free energy γ on the surface of the resin molded product, the polar component γ ^p and the dispersion component γ ^d of the surface free energy γ are obtained by the Owns and Wend method, and then the polarity calculated by the following formula (1). A squeaking sound evaluation method, characterized in that the squeaking sound is evaluated by each value of the parameter S and the surface free energy γ.
S = γ ^p / γ = γ ^p / (γ ^p + γ ^d ) (1) The squeaking sound evaluation method according to claim 1, wherein when the surface free energy γ is 50 mJ / m ² or less and the polarity parameter S is 0.2 or less, it is determined that squeaking noise is unlikely to occur.

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