TSH1562G Oil Stain Resistance Test Method for Interior Part Paint

The Toyota engineering standard, “TSH1562G Oil Stain Resistance Test Method for Interior Part Paint,” describes a test method for evaluating oil stain resistance on painted interior automotive parts. This standard includes a standardized procedure to assess how well painted surfaces (typically interior trim, panels, switches, buttons, etc.) resist staining or discoloration when exposed to oil, grease, or similar contaminants common in real-world vehicle use (e.g., from hands, lotions, food residue, or maintenance lubricants).

This standard is part of Toyota’s broader package of material and paint quality standards for interior components, ensuring long-term appearance, durability, and customer satisfaction.

This testing method is particularly applicable to the following:

• Painted plastic parts
• Interior surfaces that are frequently touched or prone to contact with oily substances.
• Suppliers and first-tier manufacturers that supply painted components to Toyota assembly plants.

The TSH1562G standard is included in lists of automotive material testing methods used by laboratories, along with related Toyota standards such as the following:

• TSH3130G defines paint film quality requirements (such as acceptance classes and appearance criteria) for interior painted parts.
• TSH1564G Fogging test method for interior paintwork
• TSH1583G Weather resistance / lightfastness test

In general, oil stain resistance tests in the automotive industry follow this approach:

• A controlled amount of a specified reference oil (or artificial sebum/oil mixture) is applied to the painted test surface.
• Contact is permitted for a specific period of time and at a specific temperature (e.g., 24 hours at room temperature or at a high temperature).
• The contaminant is removed using a standardized cleaning method (mild detergent, with the specified cloth/wipes).
• The surface is evaluated visually and sometimes instrumentally in the following aspects:
• Permanent staining/discoloration
• Change in brightness
• Color shift (color value measured using a spectrophotometer)
• Surface deterioration or erosion
• Results are classified according to pass/fail criteria or rating scales defined in the relevant performance standard (typically cross-referenced with a standard such as TSH3130G or similar).

Generally, requirements for Class A (highly visible, frequently touched) surfaces are stricter than for hidden or less critical areas.

The TSH1562G standard is commonly used by:

• Automotive paint and coating suppliers
• Interior trim manufacturers (e.g., plastic injection molding companies with in-mold painting or post-painting processes)
• Toyota supplier qualification or production part approval process tests are conducted by third-party testing laboratories.
• Toyota and its first and second-tier supply chain for quality assurance.

For those working on Toyota projects, supplying interior painted parts, or conducting material qualification tests, the TSH1562G standard is one of the fundamental methods to follow for grease-related durability.

In short, the TSH1562G standard is part of a group of Toyota paint performance standards that ensure interior coatings maintain their appearance and durability when exposed to oils, greases, or similar contaminants during vehicle use. Such contaminants can originate from human contact (skin oils, cosmetics), lubricants, or maintenance products.

Automotive interior components such as instrument panels, door panels, consoles, and control panels are frequently touched and exposed to oily substances. This standard ensures that coatings applied to these components do not discolor, soften, or deteriorate upon exposure.

The main objectives of the TSH1562G standard are as follows:

• Assessing stain resistance: Determines whether oil or grease stains will leave permanent marks or discoloration on painted interior surfaces.
• Ensuring aesthetic durability: It preserves the visual quality of interior components throughout the vehicle's lifespan.
• Evaluating coating performance: Verifies that the paint formulation and surface treatment are suitable for automotive interior use.
• Supporting quality control: Provides manufacturers and suppliers with a consistent testing procedure to verify paint systems.

The described test method generally follows these steps:

• Sample preparation: Painted interior parts or coated test panels are cleaned and conditioned under controlled conditions.
• Oil application: A specific amount of oil or oily substance is applied to the paint surface.
• Exposure time: Under controlled temperature and humidity conditions, the oil remains on the surface for a specific period of time.
• Cleaning and inspection: Following exposure, the surface is cleaned using a specific method.
• Evaluation: Paint film is examined from the following perspectives:
• Staining or discoloration
• Surface softening
• Brightness change
• Permanent scars

The TSH1562G standard is often used in conjunction with other Toyota coating evaluation standards. For example...

• TSH1544G Nail scratch resistance test for paint films
• TSH1553G Gravel impact resistance for coatings.
• TSH1554G Thread-like corrosion resistance test
• TSH1564G Fogging test method for interior parts paint.

These standards collectively evaluate the durability, corrosion resistance, scratch resistance, and stain resistance of automotive coatings.

TSH1562G is generally applied in the following situations:

• Material qualification test for interior painted components.
• Supplier verification for coating systems.
• Vehicle development tests
• Production quality control

By verifying oil resistance, this standard helps ensure that internal components maintain a clean and high-quality appearance even after prolonged use.

In conclusion, the TSH1562G standard is a specific Toyota engineering standard that tests the resistance of interior automotive paint coatings to staining from oils and greasy substances. It plays a vital role in ensuring the long-term aesthetic durability and cleanliness of vehicle interior parts.

For many years, our organization, with its competent and experienced team, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services compliant with the TSH1562G standard to businesses.