TW201008752A - Method for producing injection-molded article - Google Patents

Abstract

To provide a method for producing an injection molded product which can nearly fundamentally determine the best position of plastic reserving and the best volume of plastic reserving in a metal mold with a desired degree of improvement and also sufficiently improve the weld strength for a thin injection molded product. The method for producing the injection molded product uses the metal mold, in which a resin reservoir is arranged to project from the vicinity of a weld part excepting the weld part, in at least one side of diversion passages until the weld part formed by confluence of a plurality of molten resin flows in a cavity, wherein the resin reservoir of the metal mold is so arranged as to satisfy the following formula (I): (Vd/V)>-71.4(V0/V)<SP>3</SP>+47.8(V0/V)<SP>2</SP>-10.0(V0/V)+0.78, when the volume of the molded product from a gate central part to the weld part is V, the volume of the molded product from the weld part to a gate central part of the resin reservoir, of V, is V0, and the volume of the resin reservoir is Vd.

Description

201008752 VI. Description of the Invention: [Technical Field of the Invention] The present invention relates to an injection molding method capable of improving the strength of a welded portion. [Prior Art] In the case of a general injection molding process, a fusion phenomenon is inevitably caused by the use of a multi-point gate. The welding is produced on the surface of the molded body, corresponding to the position of the confluent portion formed by the molten resin which is ejected from the gate to the cavity of the mold, and then merged again, even if a single-point washing is used. For example, it is also possible to perform injection molding of an injection molded article having a large partial meat ratio or an injection molded article having a buried pin. That is, the term "melting" means that the merged interface formed by the flow of the molten resin at the time of joining appears on the surface of the molded body to show the joint portion. The welding on such a molded article is often caused by the above-mentioned various factors being superposed, and it is extremely difficult to form a molded article which does not cause welding in a molded article having a complicated shape in reality. In such a welded portion, not only the so-called weld mark (Weld mark) which causes the linear pattern is damaged, but the appearance of the melted resin is only a simple merge and melts to form a hybrid. The resin forms a uniform mixture, and produces only a major problem that is far below the strength that the resin should have. For the improvement of the problem of low strength of the welded portion, the molten resin is ejected from the plurality of gates through the runner to the cavity of the mold, and corresponding to the molten resin in the mold cavity of the mold The heat of the welded portion is formed on the surface of the molded body at the position of the merged portion after the flow, and the injection molding method of the 2010 tropic liquid crystal polymer is used to make one of the above-mentioned merged molten resin streams After the confluence portion forms a substantial confluence, a volume capable of continuing to flow can be maintained to make another cavity different from the cavity in the mold, and the cavity is disposed in the vicinity of one of the plurality of gates. The method on the road is well known (please refer to Patent Document 1). Further, in the mold to be used, at least one of each of the shunt resin flow paths until the shunt resin forms a welded portion after joining is formed from the branching point of the molten molten resin to be injected, and the resin protruding from the cavity of the molded product is provided. The retention portion ' contains a piston that can move forward and backward, and the resin in the welded portion is moved to break the inside of the welded portion when the resin is still maintained after the fusion is formed. A method of effectively improving the strength of the welded portion, and a mold to be used, such as the alignment of the resin or the filler, is also known (see Patent Document 2). Another method for improving the strength of the welded portion is to eject the molten resin from the plurality of gates through the flow path into the cavity of the mold, and corresponding to the flow of the molten resin in the cavity of the mold. In the injection molding method of the thermoplastic resin composition in which the welded portion is formed at the position of the merging portion, in order to allow one of the merged molten resin streams to form a substantial merging in the merging portion, A method of retaining a resin retention portion that can continue to flow, and projecting the resin retention portion to sigh on a cavity or at least one flow path of the mold is also known. CITATION LIST Patent Literature PATENT DOCUMENT PATENT DOCUMENT PATENT DOCUMENT PATENT DOCUMENT PATENT DOCUMENT PATENT DOCUMENT PATENT DOCUMENT PATENT DOCUMENT PATENT DOCUMENT PATENT DOCUMENT PATENT DOCUMENT Problem solved:

The method of Patent Document 1 is not applicable to a thickness of 3 mm or less, and the method of Patent Document 3 does not have a precedent for a thin molded article having a thickness of 4 minutes or less. On the other hand, when the method described in Patent Document 2 is applied to a thin molded article, the strength of the welded portion cannot be sufficiently improved. However, when a thin precision molded article such as a thin connector is used for lamination, problems such as cracking occur. Further, in recent years, various components have been thinned, so that the improvement of the fusion strength of the thin molded article during the forming operation is a technique which is sought to be improved. Further, the methods of Patent Documents 2 and 3 relate to a technique of continuing the flow after the resin is joined. In the mold, the position and volume of the resin retention portion are the curing speed of the resin, the volume of the molded article, and the temperature of the resin. Forming conditions such as mold temperature and injection pressure are related to each other, so it is difficult to specify them precisely. Therefore, it is also a technique pursued to easily and accurately set a high-quality injection molded article in order to accurately set the desired resin retention portion position with respect to the desired degree of improvement. In particular, when the method of Patent Document 2 is used, if the volume of the resin retention portion is increased, 'there may be a large amount of the resin retention portion, although the resin can be moved in the fusion portion. Increasing the consumption of resin does not meet the actual needs [so it is a technology pursued to use the small resin of the 201008752 as much as possible to improve the splicing strength. An object of the present invention is to provide a method for producing an injection-molded article, which solves the above-described problems, and which can accurately set the position of the resin retention portion and the volume of the resin retention portion in an almost exact manner. In order to solve the above problems, the present inventors have made intensive studies to improve the welding strength of the thin injection molded article. As a result, the method for producing an injection molded article is located in a cavity of a mold to be used, and is located at a branching path before a plurality of (4) resin flows to form a welded portion, and is close to the molten portion. The resin storage portion is provided at the position of the fused portion, and the volume of the molded product from the center portion of the rinsing portion to the welded portion is v, and the center portion of the injection port from the self-melting portion to the resin retention portion is formed. The volume of the molded article up to this is set to V. When the volume of the resin retention portion is set to ^, if the resin retention portion is arranged to conform to the following formula (1), the above problem can be solved by the method for producing the injection molded article. And can further achieve the results of the present invention. A more specific description is provided in the present invention as follows. 'Formula (I): (Vd / V) &gt; - 71. 4(V〇/ V)3+ 47. 8(V〇/ V)2- 10. 〇(Vo / V) + 0. 78 .. (I) (1) A method for producing an injection-molded article, in which a plurality of molten resin flows in a plurality of molten molds to form a fusion portion, at least one branching path of 201008752 Outside the portion, the protruding resin retentate portion is provided near the welded portion, and the volume of the molded product a from the center portion of the gate to the welded portion is ν', and the self-dissolving portion of the v is added to the resin retention portion. In the case where the volume of the resin-retaining portion is Vd, the resin-retaining portion is disposed so as to conform to the method of producing an injection-molded article of the following formula α). Formula (I): (Vd/Y)&gt; -71.4(V〇/V)3+47.8(V〇/V)2-1〇.〇(V〇/ V ) + 0. 78 ...(I (2) A method for producing an injection molded article, which is located in a cavity of a mold to be used, before a molten resin flows in a plurality of places to form a refining portion

At least one of the branching passages is provided with a protruding resin retaining portion near the welded portion I outside the welded portion, and the volume of the molded article from the central portion of the gate to the welded portion is set to V, and the aforementioned V When the volume of the molded article from the center of the injection port to the center of the injection port of the resin storage portion is set to be L, the resin retention portion is disposed so as to conform to the following formula (Π). A method of manufacturing an injection molded article. Formula (Π): V)+ 0. 66 CVd/Y)&gt;-35.6(V〇/V)3+27.〇(v〇/v)2_6/56(v〇(Π) (3) When the foregoing When the value of (WV) is 〇·1〇 or more η 17 υ Μ Μ υ 17 or less, the manufacturing method of the injection molded article described in (1) or (2). (4) When the above (vd/) When the value of v) is 〇.10 or more and 25 or less, the method for producing an injection-molded article according to any one of (1) to (3). 201008752 (5) using a liquid crystal polymer as an injection resin, and the injection molding described above When the thickness of the product is less than 1 mm, the method for producing an injection-molded article according to any one of the above-mentioned items, the effect of the invention is as follows: In the hole, at least one of the branching passages is formed by a plurality of molten resin flowing together to form a welded portion, and a protruding resin (four) portion is provided at a position close to the welded portion except the welded portion, and the 胄 can be used for the period of time The degree of improvement in the welding strength is almost exactly determined by setting the position of the resin retention portion and the volume of the resin retention portion on the mold to be used. The welding strength can be sufficiently improved even for an extremely thin injection molded article of less than 1 nm. [Embodiment] The following is a detailed description of an embodiment of the present invention, but the present invention should not be subjected to the following examples. The present invention is directed to a method for producing an injection molded article, which is characterized in that it is within the scope of the object of the present invention. At least one of the branching passages before the molten resin flows in a plurality of streams to form a welded portion, and a protruding specific resin retaining portion is provided outside the welded portion near the welded portion. [Mold] The injection molded article according to the present invention In the mold used in the production method, 'the resin retention portion is as described above. If the resin retention portion is not formed, the resin is aligned in the welded portion to form an angle of 201008752 with the flow direction, so The interaction of the interaction entanglement and the like is less, and the phenomenon of the strength is low. In the present invention, The manner in which the grease flows into the tree-retaining portion allows the resin to cause the direction of the flow direction of the resin in the welded portion to improve the strength of the welded portion. Further, the resin retains an angle perpendicular to the resin flow direction in the vicinity of the resin retention portion. The alignment, that is, the alignment toward the injection port of the resin retention portion, is provided in the resin retention portion outside the fusion portion and close to the fusion portion, thereby disturbing the alignment of the resin in the fusion portion and enhancing the resin The mold is used to prevent the strength of the melted portion from being lowered. The mold used for producing the injection molded article of the present invention is characterized in that the volume of the molded article from the center portion of the gate to the welded portion is v, and The volume of the molded article from the middle fusion portion to the center of the injection port of the resin retention portion is set to v. The volume of the resin retention portion is set to 1 field = and the resin retention portion is arranged to conform to the following formula ( )). The formula &quot;7 is expressed in the field where the bending strength of the molten portion reaches 40% or more of the bending strength of the other portion. Further, after the weld portion is produced to cause the bending strength to be lowered, the degree of the residual bending strength is expressed by the retention ratio, that is, the value obtained by (the bending strength of the welded portion / the bending strength of the other portion) x l 〇〇 % is used, for example. In the case of the following formula (I), it is a field indicating that the retention ratio is 40% or more. Formula (I): (Vd/V)&gt; -71. 4(V〇/Y)3+47.8(V〇/ V)2-1〇.〇(Vo/ V)+〇.78 ) Used in the mold In the formula 201008752 in which the resin retention portion conforming to the above formula is provided, it is ensured that the f-bending strength of the welded portion reaches 40% or more of the bending strength of the other portion. In addition to the fact that the strength of the welded portion can be greatly improved, the optimum resin retention portion position and the resin retention portion volume in the mold can be set almost exactly for the desired degree of improvement. The method of measuring the bending strength of the welded portion f is as described later, and the obtained bending strength value is measured by the method. Further, when the position of the resin retention portion in the mold to be used is arranged to conform to the following formula (when m is used, the bending strength of the welded portion of the injection molded article produced can reach 5 % or more of the bending strength of the other portion. It is an ideal method to improve the strength of the welded portion in one step. The same formula (Π) as in the case of the above formula (I) can mean that the bending strength of the welded portion reaches 50% or more of the bending strength of the other portion. Field. Formula (H):

(V, / V) &gt; -35.6 (V 〇 / V) 3 + 27. 〇 (Vo / V) 2-6.56 (VV) + 0. 66 . "(Π) Intensity can be targeted by the above formula It is desired to achieve the bending of the welded portion, and it is easy to set the position of the resin retention portion.

The volume of the resin retention. Further, as will be described later, the amount of the resin which is additionally unnecessary is suppressed by optimizing the volume of the resin retention portion, and the desired effect of improving the strength of the welded portion is obtained. In the method for producing an injection-molded article according to the present invention, the range of V()/V is usually changed as appropriate depending on the degree of improvement of the fusion strength of the injection-molded article desired. For example, when the retention ratio of the strength of the joint portion of the molded article must be 40% or more, the manufacturer of the resin retention portion and the volume of the resin retention portion can be freely set as long as the above formula (]) is satisfied. In this way, v. The range of /v is preferably 0.1 〇 or more 〇.17 or less. Although it is well known that the larger the volume of the resin-retaining portion is, the more the amount of movement of the resin disturbs the resin alignment, and the strength of the welded portion is more easily improved, but as shown in Figs. 4 and 5 It can be clearly seen that when Vc/V is in the above range, the effect of the strength and improvement of the high-welding portion can be achieved while suppressing the volume of the resin retention portion. Further, as apparent from Fig. 5, in order to achieve a retention ratio of 4% or more, the range of Vd/v should be 〇 65 or more. Similarly, as can be seen from Fig. 5, ν of 50% or more can be achieved. The range of / v should be above 0. 085. It can also be seen clearly by the 4th and 5th, when V. The range of /V is more than the above 〇·10 or more 17. 17 or less, because the retention rate is up to 40% or more, 50% or more is broad, and it is highly desirable to achieve the above or above retention rate. . In the method for producing an injection-molded article according to the present invention, the range of vd / V is usually appropriately changed depending on the degree of improvement of the desired weld strength, but it is preferably 〇1 or more and 0.25 or less. Further, although the volume of the resin retaining portion is larger as compared with the volume of the injection molded article, the strength of the welded portion is more easily improved as described above, but if the volume of the resin retaining portion is large, additional consumption is caused. More resin, resulting in an unfavorable cost increase. ¥ V〇/V is in the range of 〇.1〇 or more and 0.15 or less, and Vd/V is in the range of 0·10 or more and 0.25 or less, because it can obtain a very high weld joint strength improvement effect, and can suppress the extra Unwanted resin consumption is 11 201008752, so it is ideal. Although the position of the stagnant stagnation portion is determined according to the relationship with the volume between the resin retention portions, when the distance from the self-dissolving portion to the resin retention portion is too long, the effect of the resin aligning portion is disturbed by the resin retention portion. If it is difficult to influence the welded portion due to the distance relationship, there is a disadvantage that the volume of the resin retaining portion must be made very large. Further, when the distance from the dissolution joint to the resin retention portion is too short, that is, v. When /v is less than 〇·, the flow of the resin along the fusion portion is disturbed by the flow of the resin, and it is difficult to produce an alignment perpendicular to the fusion portion. The term "distance of the resin retention portion" means the distance from the center portion of the injection port of the resin retention portion to the fusion portion. In the mold used in the present invention, a plurality of resin retention portions may be provided. When a plurality of resin retention portions are provided, although it is possible to provide a complicated tree in the split tree of two f, it is preferable to set it on the female flow circuit of 4 and along the welded portion as much as possible. . The thickness of the injection port for the connection mold and the tree-shaped retention portion is not particularly limited, but the thickness of the injection port is preferably in a range in which the resin can be kept flowing. When the thickness of the injection port is tightened, a large pressure difference is generated between the pressure inside the resin retention portion and the fortification force in the cavity, so that the resin is more likely to flow, and the alignment of the resin flow direction is more likely to occur in the welded portion. The alignment of the resin is disturbed in the vicinity of the resin retention portion, and the interaction between the resins is enhanced to achieve an effect of improving the weld strength. The mold used in the present invention as described above can be applied to various known thermoplastic plastic tree shapes, and in particular, it is effective for the article in which the molding method causes a sharp decrease in the strength of the welded portion. For example, the crystalline resin and the material are subjected to VL - ^ ^ in the formation of the liquid crystalline polymer, and the molecular counties of both sides of the cold stone portion of the milk stone are &gt;. Since the fusion grafting is performed, the strength of the welded portion is lower than that of the other portions. However, when the molding method and the mold of the present invention are used, the alignment in the fusion portion can be efficiently obtained (4), and sufficient = strong:. In addition, when an inorganic filler thorn is used, in particular, when a fibrous "," plastic resin is used, the inorganic filler, particularly filled along the fusion portion, tends to produce the same _, and the present f-method and mold The molding of the resin composition is extremely excellent [injection molded article] The shape and the like of the injection molded article which can be produced by the production method of the present invention are not particularly limited, and the production method of the present invention can be applied to various shapes. The molding of the molded article is injected. ❿ In the method described in the above-mentioned Patent Document i, when the thickness of the injection molded article is extremely thin, the effect of improving the welding strength cannot be obtained. However, when the method for producing the injection molded article of the present invention is used, even if it is not The thin injection molded article of _ thickness can also improve the welding strength. Further, the step can improve the welding strength of the injection molded article having a thickness of less than 0.5 mm. Further, the feature of the present invention is that such an improvement in the bonding strength can be achieved even in the case of a thin injection molded article. According to the injection-molded article obtained by the production method of the present invention, the strength of the welded portion can be greatly improved. Compared with the case where the resin retention portion is not provided, the use of the present invention 4 can achieve the improvement of the refining strength of &amp; 3 # or more, and the design of the volume of 201008752. Further, it is possible to further improve the welding strength by four times or more via the position of the resin retention portion. The production method of the present invention is applicable to the production of an injection molded article using various resins as described above, but is particularly suitable for a thin meat connector which is weak in strength and which is liable to cause cracking during fitting (c〇). It is preferable to use a fine molded article such as nnec = d. Further, the thin meat connector i' using the liquid crystalline polymer as described above can also improve the bonding strength, so that the production method of the present invention can be suitably applied.

In the method for producing an injection-molded article of the present invention, when the mold having the resin retention portion as described above is used, the curing speed of the resin, the molded product capacity, and the resin temperature, the mold temperature, and the discharge pressure are not obtained. The forming conditions and the like are particularly limited. EXAMPLES The present invention will be further illustrated by the following examples, but the present invention is not limited by the examples. <Materials> Liquid crystal resin ("VectraE 13〇i", product of PoiyPlastic Co., Ltd.) <Forming method> The injection molded article in the following evaluation example is manufactured by Sodick Plustech Co., Ltd. using the mold and molding machine shown in Fig. 1 "TR1〇〇EH"), and formed according to the following conditions. The size of the obtained molded article was 50 jobs x 5 (the thickness shown in the table below). When the thickness of the molded article is changed, the "cover product and the flow path" shown in the first circle are replaced, and when the position of the resin retention portion is changed, the "tree" shown in the first figure is replaced. In the case of changing the volume of the resin retention portion, the length of the resin retention portion is changed by changing the length of the eject pin of the portion, and the depth of the resin retention portion is changed. In the position, the molded article is obtained by a mold in which the resin staying portion is not obtained, and is confirmed. <Forming conditions> Forming temperature: 350. (:

Injection speed: lOOnjm / sec Mold temperature: 70 * t Cycle time: 14 seconds The position of the resin retention part and v. The relationship between /V and the relationship between the depth of the resin retention portion and Vd / V are shown in Tables i and 2, respectively. Table 1 :

Molded product thickness 1.5 coffee t 0150 coffee 3) molded product thickness 0. 8 coffee t 080 coffee 3) molded product thickness 0.2iiinrt fV=20 Μη3) tree wax retention position Vo (mm3) v〇/v V〇 (mm3) V〇/v V„ (mm3) V〇/V 1 coffee 7.5 0.05 4 0.05 1 0.05 2 coffee 15 0.10 8 0.10 2 0.10 3mm 22.5 0.15 12 0.15 3 0.15 5mm 37.5 0.25__ 20 0.25 5 0.25 Table 2 : Thickness of the molded article 1. 5_t Forming product thickness 0. 8mit Forming product thickness 〇. 2wnnt Resin retention depth Vd (mm3) (v=l&amp;mm3) ^=§0 mm3) (V=20 nun8) Va/V Vd/V Vd/ V 1 coffee 7.065 〇. 0471 〇. 0883 0. 3533 2mm 14.13 〇· 0942 〇. 1766 0. 7065 3 coffee 21.195 〇-1413 〇· 2649 1.0598 15 201008752 <Example l &gt; Using the mold shown in Table 3 The injection molded articles of the examples and the comparative examples were produced, and the bending strength was measured by the method described below. The measurement results are shown in Table 3. [Measurement of Bending Strength] Using the bending tester shown in Fig. 2 (OrieNTEC manufactures "TENSILON RTA - 250"): test speed is 1 mm / min, span (Span) is 20 mm, fulcrum R is 2. Omm, and Figure 3 is used. The load fixture shown in the figure (the size shown in Fig. 3 is measured by using a caliper (Micrometer) ® to measure the bending strength of the welded portion in the test piece of the embodiment and the comparative example, and the welding The bending strength of the portion other than the portion was measured. Then, the retention ratio is calculated by the above-described calculation method. The bending strength and retention ratio are shown in Table 3. Table 3: — Chess weld joint bending strength (MPa) Other part bending strength (MPa) Retention rate (3⁄4) '-- Forming product thickness (nun) Resin retention depth (Caf 1) Resin retention position (Caf) Note Inlet thickness (mm) Example 1 0.2. 3 3 0.2 132.9 249.9 53.2 0.8 __3___ 0.1 116.3 186.1 62.5 Example 3 1.5 3 3 0.1 92.5 170.9 54.1 0.2 39.5 249.9 15.8 i^-J2 0.8 Resin retention unit 27.6 186.1 14.8 1.5 27.4 170.9 16.0 In Table 3, in order to be clear, it is a case where a resin retaining portion having a specific volume is provided at a specific position and it is confirmed that an improvement in the strength of the welded portion is obtained. In addition, the retention rate before the improvement (comparative example) and the retention rate after the improvement (Example) were improved. <Example 2> The influence of the thickness of the party molded article. Using the various molds of different wv and Vd/V shown in Table 4, by measuring the bend of the welded portion,

rate. The holding strength, (four) degree retention, the holding rate is not shown in Table 4. Further, the fourth circle is such that the horizontal axis is W and the vertical axis is Vd/V, and is represented by a graph in the point edge (7). The number of the knife is the retention ratio. Then, after connecting them, the graph shows a regression curve with a retention rate of 4 (U or more and a retention ratio of 5% or more.

17 201008752 P I - Comparative Example 9 0.15 0. 094 IHIi Example 22 0.15 0.18 57 Example 23 0.16 0.11 40 Example 24 0.16 0.16 50 Example 25 0.18 0.15 50 Example 26 0.18 0.11 40 Example 27 0.20 0.11 40 Implementation Example 28 0.20 0.15 50 Example 29 0.22 0.15 50 Example 30 0.22 0.11 40 Example 31 0.23 0.12 40 Example 32 0.23 0.15 50 Example 33 0.25 0.12 40 Example 34 '0.25 0.15 50 Comparative Example 10 0.25 0. 047 . 17 Example 0.25 0.14 42 Comparative Example 11 0.25 0.094 30 Comparative Example 12 0.25 0.047 27 Example 36 0.27 0.13 40 Example 37 0.27 0.16 50 Example 38 0.30 0.14 40 Example 39 0.30 0.17 a 50 Φ Via Table 4 After being converted into the fourth graph, it is clearly shown that the retention curve is in the range of 40% or more, and the approximate curve showing the retention ratio of 50% or more. Also the number in the graph is the retention rate. Figure 5 is based on the data shown in Table 4, and the production utilization rate of the company (10) is not calculated above m, _ upper body is £6, which is calculated and maintained _ up, 3 buckles, 4fllv l 60 % or more, 7 (10) or more, 8〇% or more, 40% or more, and the number shown is the retention rate, and only the area of 9% or more. The circular field shows that the field is the top of the line of the farmer's line B*. The guarantee rate is higher than the solid line. _ The heart area indicates that the present invention is still high in the fourth figure. . If the regression curve is not the same as the boundary. In the reference No. 18 201008752 · the regression curve of the representative retention rate of 4% or more and the regression curve representing the retention rate of 50% or more, and the retention rate shown in the fifth paragraph The regression curve of 4 (U and above) and the representative retention rate of 5 (10) or more are not strictly the same, but are equivalent to the range shown in Figures 4 and 5. From the regression curve It can be clearly confirmed that when the v&quot;v is in the range of 〇1 to .17, the weld strength can be improved while suppressing the volume of the resin retention portion on the one hand, and the resin retention portion can be confirmed. The larger the volume, the higher the welding strength improvement effect. <Example 3> The injection molded articles were produced using the molds having the injection ports of different thicknesses shown in Table 5. Then, the bending strength of each molded article was The retention ratio is shown in Table 5. Table 5: -------- Chess V〇/V WV Retention ratio Product thickness (nan) Resin retention depth (coffee) Resin retention position (Caf 1) Thickness (sun) Example 40 1.5 2 3 0.1 0.1 0.14 Cl 7 Example 41 1.5 2 3 0.4 0.1 0.14 〇1· { ΑΛ Ο Comparative Example 13 1.5 2 3 0.75 0.1 〇. 14 41. 〇 Example 42 0.8 2 3 0.1 39.5 0.26 33. 8 Example 43 0.8 2 3 — _0, 4 27.6 0.26 OU. 1 46. 5 Comparative Example 14 0.8 2 3 0.75 27.4 0.26 U 1 From the results of Table 5, it can be clearly confirmed that the thinner the thickness of the injection port, the greater the weld strength improvement effect. [Description of Schematic] 19 201008752 Fig. 1 is a diagram of a mold used in the practice of the present invention, (a) is a front view, (b) is a cross-sectional view taken along line A-A. Fig. 2 is a review of a molded article Bending tester used for strength. Fig. 3 is a load jig for evaluating the strength of a molded article. Fig. 4 is a graph showing the relationship between (Vc &gt;/V) and (Vd/V) and retention. Fig. 5 is a graph showing the relationship between (Vc/V) and (Vd/V) and retention ratios obtained by calculation.

Claims (1)

201008752 VII. Patent application scope: 1. A method for manufacturing an injection molded article, wherein at least one branching path before the molten resin is merged to form a welded portion in a cavity of a mold used therein, in the welded portion In addition, a protruding resin retaining portion is provided at a position close to the welded portion, and a volume of the molded article from the center portion of the gate to the welded portion is V, and the self-melting portion is transferred to the resin retaining portion among the V portions. The volume of the molded product up to the center of the inlet is set to % v. When the volume of the resin retention portion is set to vd, the resin retention portion is arranged to conform to the following formula (I): (Vd / V) &gt; - 71.4 (Vo / V) 3 + 47.8 (V〇 / V) 2-10.0 (v 〇 / V) + 0.78 (I). 2. A method for producing an injection-molded article, wherein at least one of the manifolds in the cavity of the mold to be used is located at a plurality of branches before the molten resin flows and forms a welded portion, and is adjacent to the fusion portion outside the fusion portion The protruding resin retaining portion is provided at a position, and the volume of the molded product from the center portion of the gate to the reaching portion is V, and the self-welding portion is at the center of the injection port of the resin retaining portion. The molded article volume is set to V. When the volume of the resin retention portion is Vd, the resin retention portion is arranged to conform to the following formula (Π): (Vd / V) &gt; - 35. 6 (V〇 / Y) 3 + 27. 0(V〇/ Υ)2 — 6.56(V〇/ V) + 0. 66 ...(Π ). 3. The method for producing an injection-molded article according to the first aspect of the invention, wherein the above (V./V) is 0.10 or more. 4. The method of manufacturing an injection-molded article according to claim 1, wherein the (Vd/V) is 0.10 or more and 0.25 or less. 5. The method of producing an injection-molded article according to claim 1, wherein the thickness of the injection-molded article is less than 1 mm, and the injection resin used is a liquid crystal polymer. twenty two