TPO Primer Composition for Strong Bonding to TPU and Polyester
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Solution Overview
Problem
TPO materials exhibit poor adhesion to substrates made of other materials due to low surface energy, limiting their use in applications requiring higher tensile strength and stability, such as conveyor belts and automotive parts, and existing adhesion promoters are not effective on new TPO surfaces.
Innovation Solution
A composition comprising anhydride-modified polyolefin, anhydride-modified styrenic block copolymer, and an isocyanate-containing crosslinker, dissolved in a specific solvent mixture, is used to promote adhesion between TPO and other plastics like TPU, polyester, or PU.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If simple mechanical joining (rivets, screws, or nails) is used to adhere TPO to substrate, then the joining method is easy to implement, but it does not form intimate contact between TPO layer and substrate over the entire contact surface
Solution Approach 1:
The patent introduces an adhesion promoter composition as an intermediary substance applied between the TPO layer and the substrate. This composition contains specific chemical compounds that facilitate bonding, creating a chemical bridge rather than relying solely on mechanical fastening. The intermediary composition enables intimate contact and strong adhesion across the entire contact surface while maintaining ease of application through liquid or spray forms.
2Reliability
If aqueous or solvent-based acrylic latex coating solutions are used to overcoat TPO for repair, then the coating can adhere to TPO and crosslink to form elastomer, but the adhesion is markedly better on aged TPO than on new TPO, indicating surface modification is required
Solution Approach 1:
The patent performs preliminary action by pre-modifying the TPO surface through application of the adhesion promoter composition before the final coating or bonding operation. The composition contains compounds that react with or adhere to the TPO surface, creating a prepared layer that enhances subsequent adhesion. This eliminates the need for complex surface modification procedures like sandblasting or chemical etching that would be required for new TPO surfaces.
3Strength
If chlorinated polypropylene adhesion promoter is used to overpaint TPO parts, then the paint can adhere to TPO, but the composition and application process become more complex
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the adhesion promoter. Instead of using traditional chlorinated polypropylene, the invention employs a composition with specific functional groups and molecular structures that optimize adhesion to TPO. The composition parameters (chemical composition, molecular weight, functional group content) are adjusted to achieve superior adhesion while simplifying the overall system and reducing application complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition provides strong and durable adhesion between TPO and other plastics, enhancing the tensile strength of conveyor belts and enabling effective bonding in automotive applications without requiring surface modification of TPO.
Implementation Method 1
a composition comprising an anhydride-modified polyolefin, an anhydride-modified styrenic block copolymer, and an isocyanate-containing crosslinker
Implementation Method 2
an isocyanate-containing crosslinker
Implementation Method 3
isocyanates and anhydrides or carboxylic acids can be reacted together, particularly in presence of suited catalysts, to form polyamides or polyamide-imides, respectively
Data Source
AI summary
A composition in the form of a solution or dispersion, comprising an anhydride- modified polyolefin, an anhydride-modified styrenic block copolymer, and an isocyanate-containing crosslinker, wherein the anhydride-modified polyolefin and anhydride-modified styrenic block copolymer are present in a total amount in the range of 7% to 18% by weight in total, based on the composition, and in a weight ratio of anhydride-modified polyolefin to anhydride-modified styrenic block copolymer which is in the range of 2:1 to 6:1; the weight ratio of isocyanate- containing crosslinker to the sum of anhydride-modified polyolefin plus anhydride- modified styrenic block copolymer is in the range of 0.2:1 to 0.5:1; and the solvent comprises a ketone as first solvent and an alkylbenzene or an alkane solvent. The compositions are useful for adhering TPO to TPU, polyester or PU. The composition can be used in a process of bonding a first part or coating of a TPO to a second part or coating of TPU, polyester or PU, using heat and optionally pressure, wherein the adhesion has improved peel strength.