The most commonly used plastic materials for cosmetic containers can be divided into two categories: soft materials and hard materials.

The typical soft materials are polyethylene, polypropylene, etc. Their appearance features are:

1. Appearance characteristics after processing: PE polyethylene white waxy translucent material, soft and tough, slightly malleable, lighter than water and non-toxic. You can match colors, but the brightness of colors is poor. PP polypropylene transparent or translucent material, excellent bending performance. After color matching, the material is bright in color. Shanghai jahwa United Co., Ltd. Shen Xiaoming

< second > typical hard materials include ABS acrylonitrile-butadiene-styrene polymer, PMMA polymethyl methacrylate, etc. Their appearance features are:

1. Appearance characteristics after processing: ABS material is opaque and light ivory. Can be matched with colors to become other products with bright colors and high gloss. It has the characteristics of toughness, rigidity and hardness. PMMA is transparent, like glass, and has the best transparency among plastics, but its surface hardness is low. It is easy to be scratched by hard objects.

2. Container molding method: injection molding.

3. Surface decoration and post-treatment effect: containers can be printed, bronzed, labeled and painted without special surface treatment.

4. Scope of application: ABS material has poor compatibility with cosmetic interior materials. Suitable for plastic covers, container shells, etc. Generally, PMMA material shows light transmission characteristics similar to glass, which is used to make thick-walled plastic parts.

Second, the container material molding process

The most common molding methods are injection molding, hollow molding and injection stretch blow molding.

(1) Key points to be paid attention to in injection molding:

2. Container molding methods: injection molding, hollow molding and injection stretch blow molding.

3. Effect of surface decoration and post-treatment: After surface treatment, the container can be printed, bronzed and labeled (or in-mold labeled).

4. Scope of application: Good compatibility with interior decoration materials. Suitable for outer cover, inner cover, inner container, seal, plastic plug, shampoo bottle, etc. But it is not suitable for containers of solvent-based nail polish, polishing water and other products.

When designing the structure of injection molding products, we must pay attention to the contents that will affect the appearance quality of plastic products: gate position, parting surface position and product wall thickness.

1. Aircraft carrying passengers

Point feeding: The plastic flow filling performance is good when injected with external center feeding, which is suitable for products with general top requirements. There will be traces of the material head at the position of the inlet, which will affect the printing and bronzing of the top surface to some extent.

Point feeding: inner (upper) center feeding overcomes the shortcomings of outer center feeding. However, the die processing is complicated and the feed inlet is too long.

Side feeding: Latent feeding is suitable for soft plastics. In the molding process of plastic parts, there will be many defects, such as joint marks, poor exhaust, paste at the top corner, and the residual marks at the side feeding position of plastic parts are not obvious.

Side feeding: bottom feeding is suitable for products with special requirements on the top surface, which is inconvenient to place the entrance. Plastic products are prone to some defects, such as joint marks, poor exhaust, top corner burning, and residual traces of material heads on the parting surface of plastic products.

2. Location of parting surface

Plastic is molded in a mold. In order to take the plastic out of the mold, the parting surface of the mold is called the mold and the parting line is called the plastic part.

The parting surface must be set where the outline of plastic parts is the largest. Only in this way can the plastic parts be taken out of the cavity smoothly.

The position of parting line is perpendicular to the mold opening direction, parallel to the mold opening direction, and inclined to the mold opening direction.

Parting lines include straight lines, broken lines and curves.

The location of parting line will directly affect the appearance effect and should be located on the plastic parts.

The position where a surface is not observed. The parting line should be located at a position convenient for mold processing and flash processing.

3. Wall thickness of the product

Thermoplastics can be made into thin-walled containers with a wall thickness of 0.25mm..

However, the design of plastic plastic parts is generally not less than 0.6 ~ 0.9 mm, and 1.5 ~ 4.0 mm is often taken.

In addition to the necessary thickness, plastic containers also require uniform wall thickness, not too thick or too thin. Otherwise, stress concentration, cracks, deformation and other defects will occur due to uneven shrinkage of plastic. Of course, it is impossible for any plastic container to achieve completely uniform wall thickness. If the plastic structure must have uneven thickness, smooth transition should be taken to avoid sudden changes. It is suggested that the thickness unevenness of thermoplastic joint is1:1.2 ~1:1.5.

(2) Key points that should be paid attention to in the process of blow molding:

When designing the structure of blow-molded products, we must pay attention to the contents that will affect the strength of plastic products: the inflation ratio of blow-molded containers and the vertical load strength of products.

1. Inflation ratio and elongation

Blow-up ratio refers to the ratio of the maximum diameter of plastic parts to the diameter of parison. The proportion should be chosen properly. If it is too large, the wall thickness of plastic parts will be uneven, and the processing conditions will be difficult to master. The general inflation rate is 2: 1 ~ 4: 1, but 2: 1 is commonly used.

In injection-stretch blow molding of hollow plastics, the ratio of the length of plastic parts to the length of parison is called extension ratio. The selection of extension ratio is very important. After determining the elongation, determine the parison length.

2. Vertical load strength

For plastic bottles, it must bear vertical loads from many aspects, among which the pressure from the feeding nozzle and the sealing mechanism is the first.

The potential fragile factor in strength is the inclination angle of the bottle shoulder. At the joint between the bottle body and the bottle shoulder, a larger bending radius (R) should be adopted as far as possible to reduce the stress at the turning part, thus improving the vertical strength of the bottle.

The bottom structure also has obvious influence on the strength of the bottle, and the acute angle between the bottle and the bottom will weaken the vertical strength of the bottle. Therefore, in order to transfer the vertical load evenly, the bottom corner of the bottle should be gradually bent and the curvature should be large.

Bottle body structure; For bottles with skin lines or wrinkles, the vertical load strength of the bottle decreases, but the rigidity of the bottle can be improved. If the form of mutation is adopted, the trademark area is obvious, but radial mutation will lead to seam convergence and stress cracking.

Three. Laws and standards involved

In the initial stage of product structure design, firstly, the design input content should be clear:

The physical form of the container contents.

Nominal weight (g g weight) or volume (ml ml) of the contents.

Product quality assurance requirements. At the same time, we should understand the national, local and enterprise regulations and standards related to products.

In the Order of the State Bureau of Technical Supervision (No.43), the net content of products is clearly defined.

Fourthly, the capacity design of the container.

Enterprises will clearly put forward product identification requirements when releasing product development plans. The conventional form is: the product whose internal substance does not flow at room temperature is in weight (g g weight, kg kg), and the product whose internal substance can flow at room temperature is in volume (ml ml ml, l liter).

& ltI > product density:

In the product structure design, when the product takes the weight (gram weight) as the unit, it is necessary to convert the required content weight into unit of volume. Volume (ml) = weight (gram weight)/product density. Because after the container is formed, it is most convenient and accurate to detect the inner cavity space with standard distilled water.

< second > measurement of volume of packaging container:

The composition materials of cosmetic internal materials are diverse. Therefore, when designing the internal volume of the product packaging container, we should pay attention to the changes of the internal volume and shape caused by time, temperature, preparation, filling and other factors, as well as the viscosity of the internal volume, and leave an appropriate gap when designing the full mouth capacity of the container.

1. Time and temperature factors

In cosmetics, some internal substances will change in volume with time and temperature.

(1) Time factor: the powder product will become smaller with time, and the product volume within one or two days after preparation and storage is obviously larger than that of similar products stored for more than one week.

(2) Temperature factor: the volume of alcoholic water products will increase with the increase of temperature: the volume of alcoholic water products at room temperature minus 5 degrees Celsius will be significantly smaller than that at 35 degrees Celsius.

2. Preparation and filling factors

In the preparation and filling process of packaging process, the internal objects will be stirred and impacted between materials, resulting in bubbles and foams. So that the volume of the internal material changes.

(1) Formula factor: Due to the high viscosity of the internal materials, a large amount of air will be brought in during the mixing process, so a large number of bubbles will be stored in the semi-finished products, which will affect the product volume.

(2) Filling factor: Due to the inherent foaming agent component of shampoo products, the interior materials are subjected to high-speed impact during the product filling process, and a large amount of foam floats on the surface of the materials, which expands the demand space of the container.

(3) Viscosity factor of internal materials: Frosted products generally have a high viscosity, and there will be a conical protrusion on the upper surface of the internal material paste after filling, which will not disappear in a short time. Due to the high-speed operation of the assembly line, if the product combination is completed at this time, the internal paste will contact with the sealing sheet, which will affect the appearance of the combined product and cause the possibility of secondary pollution of the product. Therefore, this phenomenon should be fully considered when designing the volume of such products.

Five, the container seal design

Cosmetics industry has clear and strict requirements for container sealing performance.

The method is as follows: horizontally put the container filled according to the requirements and sealed according to the specified standards into a vacuum box, and keep it at1MP for 5 minutes when the vacuum degree in the box reaches -0. 1MP. Then take it out and observe whether there are internal substances oozing out. No leakage of internal materials is qualified.

Product sealing is a compulsory quality standard in cosmetics production industry. How to realize product sealing guarantee? The second type of sealing scheme is described below:

& ltI > gasket seal:

1. Electromagnetic induction gasket can achieve the purpose of fusion sealing, but the cost is relatively high, the packaging process is complicated, and the product mouth after fusion sealing will produce barbed burrs.

2. Pressure-sensitive adhesive gasket can achieve the purpose of welding and sealing, but its cost is relatively high and its adaptability to aquatic products is poor.

3. Foamed polyethylene gasket has many choices in elasticity and thickness, and it is a commonly used material at present.

< second > mechanical seal:

1. the material is sealed by restoring force, and the local material is deformed by external force and maintained in a predetermined form. The purpose of product sealing is achieved by using the elastic restoring force of materials.

2. The column and the ring are sealed by winding force, and the column is embedded into the ring by external force. Under the elastic deformation force of the material, the outer surface of the cylinder presses the inner surface of the ring to achieve the purpose of product sealing.

3. Material expansion force sealing, which uses external force to urge one part to deform locally and press it tightly on the surface of another part to realize product sealing.

< Third > Adaptability of packaging workflow.

Filling form and material form: in the production process, the material enters the container very quickly, so the container design should consider the defects caused by container exhaust, the collision between materials and the influence of container shape on the accumulation of filled materials during rapid filling.

Conveying reliability of conveyor belt: judge whether products can be mass-produced.

In the daily structural design, we generally adopt the process of imitation, improvement and innovation to realize the innovative design of product structure.

Comparison method of similar products-select similar samples, analyze their structural characteristics, select the essence and discard the dross. It is instructive to the structural design work.

Empathy, the self-denial method of design, transforms itself from the designer's position to a consumer who knows nothing about the purpose of the product. Find fault with your own design and find problems that may bring inconvenience to consumers. At the same time, improve and adjust their own design.

Simulated physical inspection method-a brand-new structural design scheme, usually making a model first. Then through the analysis of model samples, the requirements for improvement and adjustment are obtained. Compare and analyze the obtained data, and extract representative suggestions. Compare your own structural design scheme and make improvements and adjustments.

Structural design is a bridge between creativity and realization. Through reasonable structural design, creativity can be realized, enterprises can achieve rapid innovation, effectively reduce development costs, improve labor productivity and save production costs, effectively control the quality of finished products, and products can meet consumer demand.

When materials are transported by conveyor belt, whether the container is in a stable state during transportation will directly affect whether the packaging process can circulate normally, the labor intensity of employees and the benefits of enterprises.

Simplicity and rationality of assembly form: in the process of mass production, the matching between parts must be reasonable and concise, and the assembly should be designed in advance. Attachment connection of assembly parts shall be reliable and reasonable, and shall not be lost.