CN108024464B

CN108024464B - Shell, preparation method and mobile terminal

Info

Publication number: CN108024464B
Application number: CN201711080022.3A
Authority: CN
Inventors: 陈永红; 杨璟; 周小斌; 陈仕权; 李静
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2017-11-06
Filing date: 2017-11-06
Publication date: 2020-07-10
Anticipated expiration: 2037-11-06
Also published as: CN108024464A

Abstract

The invention provides a shell, a preparation method of the shell and a mobile terminal. The method comprises the following steps: forming an internal injection molding part through primary in-mold injection molding; by means of a second injection moulding, a support structure is formed between the inner injection moulding and the injection-moulded membrane in order to obtain the housing. Therefore, the internal injection molding part and the supporting structure are subjected to step injection molding, so that the internal injection molding part can be formed by using a material with higher melting temperature and better fluidity, and an injection molding part with a more complex structure can be formed; the supporting structure is formed by using materials with lower melting temperature and better mechanical property, so that the overall mechanical property of the shell can be ensured.

Description

Shell, preparation method and mobile terminal

Technical Field

The invention relates to the field of materials, in particular to a shell, a preparation method and a mobile terminal.

Background

With the increase of the consumption level, consumers have demanded not only diversification of functions but also higher and higher demands on appearance, texture, and the like of industrial products. For example, at present, mobile terminals such as mobile phones and tablet computers increasingly adopt integrated shells with large radians to improve user experience. In recent years, in-Mold decoration (IMT), which is also called as in-Mold 3D decoration, is widely used in the field of manufacturing mobile terminal housings. The specific structure of the product formed by IMT can be a surface hardening transparent film, a middle printing pattern layer and a back injection molding layer. Because the pattern layer is positioned in the middle, the product has high definition, good stereoscopic impression, friction resistance, surface scratch prevention, bright color for a long time and difficult fading.

However, the mobile terminal housing formed by the in-mold injection molding technology and the method for manufacturing the same still need to be improved.

Disclosure of Invention

The present application is based on the discovery and recognition by the inventors of the following facts and problems:

the shell prepared by adopting the IMT or IM L technology generally has the problems that the injection molding quality and the mechanical property of the shell cannot be considered, particularly, for the same injection molding material, if the polymerization degree is high, the mechanical property is generally good, but the melting temperature is also high, when the mechanical strength is ensured, if a plastic material with high polymerization degree is adopted for injection molding, the complex and fine injection molding structure is favorably formed, and the injection molding quality is good, but the injection molding temperature is high, the impact effect of the injection molding plastic raw material on the membrane and the ink is large, the membrane is easy to deform, the ink flushing is easy to occur, and the like.

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.

In one aspect of the invention, a method of making a housing is provided. According to an embodiment of the invention, the method comprises: forming an internal injection molding part through primary in-mold injection molding; by means of a second injection moulding, a support structure is formed between the inner injection moulding and the injection-moulded membrane in order to obtain the housing. Therefore, the internal injection molding part and the supporting structure are subjected to step injection molding, so that the internal injection molding part can be formed by using a material with higher melting temperature and better fluidity, and an injection molding part with a more complex structure can be formed; the supporting structure is formed by using materials with lower melting temperature and better mechanical property, so that the overall mechanical property of the shell can be ensured.

In yet another aspect of the present invention, a housing is presented. According to an embodiment of the invention, the housing is prepared using the method described above. Thus, the housing has all the features and advantages of the housing prepared by the method described above, and thus, the description thereof is omitted.

In yet another aspect of the present invention, a housing is presented. According to an embodiment of the invention, the housing comprises: the shell comprises a shell body and a shell body, wherein the shell body comprises an internal injection molding part and a supporting structure which are sequentially formed, the internal injection molding part is arranged on one side of the supporting structure, and the materials of the internal injection molding part and the supporting structure are different; the membrane layer of moulding plastics, the membrane layer setting of moulding plastics is in bearing structure keeps away from one side of inside bearing structure. Therefore, the shell can give consideration to the injection molding quality and the mechanical performance of the shell, and the internal space of the mobile terminal using the shell can be saved.

In yet another aspect of the present invention, a mobile terminal is presented. According to an embodiment of the present invention, the mobile terminal includes a housing, the housing is the foregoing, and a main board and a memory are disposed in the housing; the screen is arranged at the top of the shell and connected with the main board. Thus, the mobile terminal has all the features and advantages of the housing described above, which are not described in detail herein.

Drawings

FIG. 1 shows a flow diagram of a method of preparing a housing according to one embodiment of the invention;

FIG. 2 shows a schematic structural view of a housing according to an embodiment of the invention; and

fig. 3 shows a schematic structural diagram of a mobile terminal according to an embodiment of the present invention.

Reference numerals:

100: injection molding a membrane layer; 10: an inner injection molded part; 20: a support structure; 200: a housing; 1000: a mobile terminal.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

For ease of understanding, the in-mold injection process is first briefly described below:

the IMT (IM L) is a novel technology combining screen printing and injection molding, when the IMT (IM L) is used for preparing the mobile terminal shell, firstly, screen printing is carried out on a transparent sheet (a printing material used for forming an injection molding membrane) to finish image-text transfer, then, the transparent sheet with a pattern layer is subjected to molding treatment to form the injection molding membrane, then, the injection molding membrane is placed in an injection mold and fixed on the shell body, the pattern layer of the injection molding membrane is arranged away from the shell body, the injection molding membrane can be finally kept on the shell body (namely, the IMT technology) or can be provided with a structure such as a release film layer on the pattern layer, the release film layer is removed at the later stage, and the pattern layer of the injection molding membrane is only kept on the shell body (namely, the IM L technology), wherein, the shell body can be formed in advance or in an in-mold injection molding process, injection molding materials are injected from an injection molding opening of the mold, and the injection molding space of the whole mold is filled, and finally, the injection molded shell is polished to obtain the mobile terminal shell with certain image-text appearance effect.

In one aspect of the invention, a method of making a housing is provided. According to an embodiment of the invention, with reference to fig. 1, the method comprises:

s100: first time of in-mold injection to form an internal injection molding part

According to an embodiment of the invention, in this step the inner injection molded part is first formed by a first in-mold injection. As mentioned above, the casing is prepared by step injection molding, which is beneficial to ensuring the injection molding quality and the overall mechanical performance of the casing. The inventors have found that it is possible to use a material with a higher melting temperature, and to form the inner injection moulded part first by in-mould injection moulding. Because the internal injection molding part is not in direct contact with the injection molding membrane provided with the appearance pattern, the first time of in-mold injection molding can be formed at a higher temperature without worrying about negative effects on the injection molding membrane in the injection molding process.

Specifically, according to the embodiment of the invention, the injection temperature of the first in-mold injection molding can be 280-300 ℃. The material used for the first in-mold injection molding can be a first injection molding material, and the first injection molding material can include at least one of PC and ABS, as long as the injection molding temperature can be satisfied. For example, PC may be used as the first casting material, or a blend of PC and ABS may be used as the first casting material. In the above-mentioned blends of PC and ABS, the PC content may be somewhat higher in order to ensure a higher melting temperature of the first casting compound. The inventors have intensively studied and found that the inner injection-molded part formed of the above-mentioned material can have a relatively complicated structure, thereby facilitating saving of the inner space of the mobile terminal using the case. According to the embodiment of the present invention, the specific shape of the internal injection molding part is not particularly limited, and those skilled in the art can design the internal injection molding part matched with the specific mobile terminal using the housing according to the model of the mobile terminal and the arrangement condition of the internal main board, the battery and other structures, so as to save the internal space of the mobile terminal while fixing the above structures.

S200: second time of in-mold injection to form a support structure

According to an embodiment of the invention, in this step, the support structure is formed between the inner injection-moulded part and the injection-moulded membrane by a second in-mould injection moulding in order to obtain the housing. Therefore, the problems of ink impact, bubble generation and the like in the injection molding process can be relieved, and the overall mechanical performance of the finally obtained shell can be ensured.

According to an embodiment of the present invention, the temperature of the second in-mold injection may be lower than the temperature of the first in-mold injection described above. Because the supporting structure formed by the second intramode injection molding is directly contacted with the injection molding film layer, the problems of ink flushing, damage to the injection molding film layer and the like caused by overhigh injection molding temperature can be prevented.

Specifically, according to the embodiment of the invention, the injection temperature of the second in-mold injection molding can be 270-290 ℃. For example, the temperature can be 270-280 ℃. The support structure may be formed from a second injection molded material. According to an embodiment of the present invention, the second injection molding material may include at least one of PC and ABS. For example, it may be ABS, or a blend of ABS and PC. The blend of ABS and PC may have a slightly lower PC content than the first casting compound. Thereby, injection molding of the support structure can be achieved at lower injection temperatures.

According to the embodiment of the invention, on the premise that the first injection temperature is higher than the second injection temperature, at least one of the first injection material and the second injection material can meet the following condition that the first injection material and the second injection material can respectively and independently comprise PC, and the melt index of the material is less than 28g/10 min.

It should be noted that the specific chemical composition of the above materials (or plastics) constituting the first and second molding materials is not particularly limited as long as the requirements of the in-mold molding process can be satisfied and the melt index is within the above range. The particular chemical composition of the materials described above can be selected by those skilled in the art based on the particular environment in which the injection molding material will be used. For example, the plastic may be PMMA, PET, PS, etc. to meet the requirements of structures such as mobile phone back case, household appliance panel, etc. According to a specific embodiment of the present invention, the plastic may include a PC therein, for example, when preparing a housing for a mobile terminal such as a mobile phone. Therefore, the plate formed by injection molding in the mold can meet the requirement of the mobile terminal shell. According to embodiments of the invention, the plastic may have a melt index of 18 to 28g/10 min. Therefore, the material can have better fluidity and toughness when used for in-mold injection molding. Therefore, the material according to the embodiment of the invention can be used for manufacturing products with larger curvature radius or complex structures by using an in-mold injection molding technology.

It is to be noted that the term "melt index" may be obtained by testing in a manner familiar to the person skilled in the art. Specifically, the test method may be to first melt the plastic pellets into plastic fluid within a certain time (e.g., 10 minutes as used in this application), under a certain temperature and pressure (different standards of various materials, and those skilled in the art can select the plastic fluid according to specific conditions), and then to measure the number of grams (g) of plastic fluid flowing out through a circular tube with a diameter of 2.095 mm. The larger the value of the melt index, the better the processing fluidity of the plastic material, and vice versa. Therefore, according to embodiments of the present invention, the plastic material used for the IMT injection molded layer needs to have higher flowability, i.e., higher melt index.

According to an embodiment of the present invention, the plastic is formed by melt co-extrusion of a first resin and a second resin, wherein the molecular weight of the first resin is greater than the molecular weight of the second resin. It is to be noted that the terms "molecular weight of the first resin", "molecular weight of the second resin", and the like, particularly denote the molecular weight of the main polymer constituting the resin. For example, when the first resin or the second resin is a blend of two or more polymers, "molecular weight of the first resin" and "molecular weight of the second resin" refer to the molecular weight of the polymer in the resin in a mass content of 50% or more. It should be noted that the term "polymer" is to be understood in a broad sense and includes both polymers formed from a single monomer and copolymers formed from a plurality of monomers. According to the embodiment of the present invention, the components, mixing ratios, and the like of the first resin and the second resin are not particularly limited as long as the molecular weight of the first resin is larger than that of the second resin and the melt index of the formed plastic is less than 28g/10 min. Therefore, the proportion of the first resin with larger molecular weight and the proportion of the second resin with smaller molecular weight can be adjusted according to the specific chemical compositions of the first resin and the second resin, so that the melt index of the formed plastic meets the requirement of the in-mold injection molding process. The inventors have found that other physical and chemical properties of the resin have less influence on the melt index of the finally formed plastic. Therefore, it is only necessary to make the molecular weight of the main component in the first resin and the second resin different, and a plastic with a melt index satisfying the requirement can be obtained by adjusting the mixing ratio of the first resin and the second resin.

According to an embodiment of the present invention, the first resin may be a blend including PC and ABS. The blend of PC and ABS has lower melting temperature and higher fluidity, and can meet the requirements of the IMT injection molding process. According to an embodiment of the present invention, the second resin may include PC, and the molecular weight of the PC in the second resin may be 2-5 ten thousand. Through extensive research, the inventor finds that when the molecular weight of PC in the second resin is in the range of 2-5 ten thousand, the plastic obtained after mixing the first resin and the second resin has better toughness, and is particularly suitable for forming a mobile terminal shell by using in-mold injection molding. According to an embodiment of the present invention, the molecular weight of the PC in the first resin is greater than the molecular weight of the PC in the second resin. Therefore, after the second resin containing the PC with the lower molecular weight is mixed with the first resin containing the PC with the higher molecular weight, the toughness of the first resin can be adjusted, so that the plastic mixed by the first resin and the second resin has good toughness and simultaneously has better fluidity and mechanical strength.

According to an embodiment of the present invention, the mass ratio of the first resin and the second resin is greater than 1: 1. that is, in the plastic, the mass of the first resin is larger than the mass of the second resin. The inventor finds through a large number of experiments that when the mass ratio is too large, the first resin content is too large, so that the toughness of the plastic is poor, and the sheet or the ink layer is difficult to ensure not to be impacted when the in-mold injection molding is carried out; when the proportion is too small, the content of the second resin is too large, so that the flowability of the plastic is too high, and a complex injection molding structure cannot be formed by utilizing an in-mold injection molding technology. And when the mass ratio of the first resin to the second resin is more than 1: 1, the toughness of the plastic can be improved, and other properties such as hardness, mechanical strength and the like of the plastic can be ensured not to be influenced.

According to the embodiment of the invention, the method is not only beneficial to giving consideration to the injection molding quality and the overall mechanical property of the shell, but also can be realized without greatly improving the existing in-mold injection molding technology: the preparation of the shell by the method according to the embodiment of the invention can be realized by adopting a double-color injection molding machine and performing injection molding step by step.

In summary, the above method has at least one of the following advantages:

(1) injection molding parts with complex structures can be prepared, and the internal space of the mobile terminal is saved;

(2) the injection molding process does not cause negative influence on the injection molding membrane, and is favorable for relieving or even solving the defects of ink flushing, thick and thin printing, bubbles and the like;

(3) the overall mechanical performance of the shell is excellent.

In another aspect of the invention, a housing is provided. According to an embodiment of the invention, the shell is prepared using the method described above. Thus, the housing has all the features and advantages of the housing prepared by the method described above, and thus, the description thereof is omitted.

In yet another aspect of the present invention, a housing is presented. According to an embodiment of the present invention, referring to fig. 2, the housing 200 may include: a housing body and an injection molded film ply layer 100. Specifically, the housing main body may include: an inner injection molded part 10 and a support structure 20.

According to the specific embodiment of the invention, the support structure 20 is in contact with the injection molded membrane layer 100, and the inner injection molded part 10 is arranged on the side of the support structure 20 away from the injection molded membrane layer 100, and the material constituting the inner injection molded part and the support structure is different.

According to embodiments of the present invention, the housing may be formed using the method described above. Thus, the housing has all the features and advantages of the housing prepared by the mold as described above, and the description thereof is omitted.

In yet another aspect of the present invention, a mobile terminal is presented. According to an embodiment of the present invention, referring to fig. 3, the mobile terminal 1000 includes a housing 200 and a screen (not shown), the housing 200 is as described above, a main board and a memory (not shown) are disposed in the housing 200, and the screen is disposed on the top of the housing and connected to the main board (not shown). Accordingly, the mobile terminal 1000 has all the features and advantages of the housing described above, which will not be described herein.

The embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention. It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "back", "top", "bottom", "inner", "outer", and the like, indicate orientations and positional relationships based on the orientations and positional relationships shown in the drawings, are used for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. For example, in the present invention, the "upper surface" of the stainless steel plate and the structures such as the stainless steel substrate, the aluminum layer, the anodized layer, etc. refer to the side of the plate or the structure facing the external environment and away from the inside of the electronic device in practical applications.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. A method of making a housing, the method comprising:

forming an internal injection molding part through primary in-mold injection molding;

through moulding plastics in the second time the inside injection molding and form bearing structure between the diaphragm of moulding plastics to obtain the casing, the temperature of moulding plastics in the first time is higher than the temperature of moulding plastics in the second time, the temperature of moulding plastics in the second time is 270 ~ 290 degrees centigrade, the temperature of moulding plastics in the first time is 280 ~ 300 degrees centigrade.

2. The method of claim 1, wherein the material of the first in-mold injection is different from the material of the second in-mold injection.

3. The method of claim 2, wherein the inner injection molded part is formed from a first injection molded plastic and the support structure is formed from a second injection molded plastic,

the first injection-molded plastic and the second injection-molded plastic are each independently selected from at least one of PC and ABS.

4. The method of claim 3, wherein at least one of the first injection molded plastic and the second injection molded plastic has a melt index of less than 28g/10 min.

5. The method of claim 4, wherein at least one of the first and second injection-molded plastics is formed by melt co-extrusion of a first resin and a second resin, wherein the molecular weight of the first resin is greater than the molecular weight of the second resin.

6. The method of claim 5, wherein the second resin comprises PC, and wherein the molecular weight of PC in the second resin is 2 to 5 million.

7. The method of claim 5, wherein the first resin is a blend comprising PC and ABS.

8. The method of claim 6 or 7, wherein the molecular weight of the PC in the first resin is greater than the molecular weight of the PC in the second resin.

9. The method of claim 6, wherein the mass ratio of the first resin to the second resin is greater than 1: 1.

10. a housing, characterized in that it is produced by a method according to any one of claims 1-9.

11. A housing, characterized in that the housing comprises:

the shell comprises a shell body and a shell body, wherein the shell body comprises an internal injection molding part and a supporting structure which are sequentially formed, the internal injection molding part is arranged on one side of the supporting structure, and the materials of the internal injection molding part and the supporting structure are different;

the membrane layer of moulding plastics, the membrane layer setting of moulding plastics is in bearing structure keeps away from one side of inside bearing structure.

12. A mobile terminal, comprising:

a housing as claimed in claim 10 or 11, wherein a main board and a memory are provided in the housing;

the screen is arranged at the top of the shell and connected with the main board.