United States Patent 4,906,775: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 4,906,775, titled "Esters of 3-tert-butyl- and 3-tert-butyl-5-alkyl-4-hydroxyphenyl (alkane) carboxylic acids with oxyethylates of polythiols," is a patent that deals with the preparation and use of specific esters as polymer stabilizers. This analysis will delve into the scope, claims, and the broader patent landscape surrounding this invention.
Background and Invention Overview
The patent, filed as application Ser. No. 07/122,724, pertains to the development of esters derived from 3-tert-butyl- and 3-tert-butyl-5-alkyl-4-hydroxyphenyl (alkane) carboxylic acids, which are combined with oxyethylates of polythiols. These compounds are designed to serve as improved stabilizers for polymers, enhancing their durability and resistance to degradation[5].
Scope of the Invention
The scope of the invention is focused on the chemical synthesis and application of these specific esters. Here are the key aspects:
Chemical Composition
The patent describes the esters of 3-tert-butyl- and 3-tert-butyl-5-alkyl-4-hydroxyphenyl (alkane) carboxylic acids with oxyethylates of polythiols. These compounds are tailored to provide superior stabilizing properties for polymers.
Preparation Method
The invention includes detailed methods for the preparation of these esters, involving the reaction of the carboxylic acids with oxyethylates of polythiols. This process is crucial for ensuring the desired properties of the stabilizers.
Use as Polymer Stabilizers
The primary application of these esters is as stabilizers for polymers. They are intended to protect polymers from degradation caused by heat, light, and other environmental factors, thereby extending the lifespan and improving the performance of polymer-based materials.
Claims Analysis
The patent includes several claims that define the scope of the invention:
Independent Claims
- Claim 1 typically describes the general structure of the esters, including the specific carboxylic acids and oxyethylates of polythiols.
- Subsequent claims narrow down the scope by specifying particular types of carboxylic acids, polythiols, and the conditions under which the esters are prepared.
Dependent Claims
- These claims build upon the independent claims, providing further details on the synthesis process, the properties of the esters, and their specific applications in polymer stabilization.
Patent Landscape
To understand the position of this patent within the broader patent landscape, it is essential to consider several factors:
Prior Art
The patent cites prior art related to similar stabilizers, such as other types of esters and polythiols. However, the specific combination and preparation method described in this patent are novel and distinguish it from prior art[5].
Related Patents
The invention is related to other concurrently filed applications by the same coassignees, such as Ser. No. 122,722, which deals with esters of 3-tert-butyl- and 3-tert-butyl-5-alkyl-4-hydroxyphenyl (alkane) carboxylic acids with oxyethylates of polyhydroxyaromatics. These related patents indicate a broader research effort in developing advanced polymer stabilizers.
Global Patent System
The patent is part of the global patent system, and similar inventions may be patented in other countries. For instance, the European Patent Office (EPO), Japan Patent Office (JPO), and other international intellectual property offices may have similar or related patents that need to be considered when assessing the global patent landscape[4].
Search and Analysis Tools
To analyze the patent landscape effectively, several tools can be utilized:
USPTO Search Tools
The USPTO provides various search tools, such as the Patent Public Search tool, which can help in identifying related patents and prior art. The Global Dossier service is also useful for accessing file histories of related applications from participating IP offices[4].
Patent Analytics
Patent analytics services can help in categorizing patents by claims and scope concepts, making it easier to identify gaps or opportunities in the patent coverage. Tools like ClaimScape® software can generate interactive claim charts to review patent coverage and determine future design opportunities[3].
Legal Status and Expiration
The patent US 4,906,775 has expired due to the lapse of the patent term, which is typically 20 years from the filing date of the application. This expiration means that the invention is now in the public domain, and the described esters can be freely used without infringing on the original patent[5].
Key Takeaways
- Invention Scope: The patent focuses on the synthesis and application of specific esters as polymer stabilizers.
- Claims: The claims define the structure, preparation, and use of these esters.
- Patent Landscape: The patent is part of a broader research effort in polymer stabilization and is related to other patents filed by the same coassignees.
- Search and Analysis: Tools like USPTO search tools and patent analytics services are essential for understanding the patent landscape.
- Legal Status: The patent has expired, making the invention public domain.
Frequently Asked Questions (FAQs)
Q: What is the main purpose of the esters described in US Patent 4,906,775?
A: The main purpose is to serve as stabilizers for polymers, protecting them from degradation.
Q: How are the esters prepared according to the patent?
A: The esters are prepared through the reaction of specific carboxylic acids with oxyethylates of polythiols.
Q: Are there related patents to US 4,906,775?
A: Yes, there are related patents filed by the same coassignees, dealing with similar stabilizers.
Q: What tools can be used to analyze the patent landscape?
A: Tools such as the USPTO's Patent Public Search, Global Dossier, and patent analytics services like ClaimScape® can be used.
Q: What is the current legal status of US Patent 4,906,775?
A: The patent has expired due to the lapse of the patent term.
Cited Sources
- In re Cellect - United States Court of Appeals for the Federal Circuit
- U.S. Patent and Trademark Office (USPTO) | USAGov
- Patent Analytics | Intellectual Property Law
- Search for patents - USPTO
- US4906775A - Google Patents
