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How to Develop Liquid-Resistant Paper Straws

Posted 06/30/2020 by Erin L'Hotta, Marketing Manager, Paper Converting

As more and more consumers are adopting an “anti-plastic” movement mindset, paper straws are becoming an increasingly important alternative. 

H.B. Fuller surveyed 1,400 consumers in Spain, Italy, France, United Kingdom, Canada, and the United States to understand their attitudes toward paper straws. The survey included consumers between the ages of 25 and 65 years old. Out of the survey respondents, 65% support the ban of single-use plastic straws. One challenge is that 47% of those surveyed said that they personally had experienced a paper straw unravel while drinking a beverage. 

Finding the Right Liquid-Resistant Paper Straw Adhesive is Critical 

To ensure a paper straw does not unravel during use, there needs to be a strong liquid-resistant adhesive holding the paper together. The paper manufacturer, paper grade, machine type, and paper color are all variables to consider when choosing the right adhesive. 

H.B. Fuller’s adhesive solutions comply with direct liquid contact regulations. While submerged in a liquid, the adhesive provides strength to ensure the straw maintains its form. It is additionally important that the adhesive bond enables straw composting after a paper straw is used. 

Paper Straw Test Methods 

Paper straw manufacturing is affected by a range of challenges, including how the adhesive is applied to the paper, the type of equipment used, the use or not of a heater, and the machine speed. Quality control testing ensures the final paper straw meets quality requirements and safety standards. When conducting a quality control test, one must use the same paper at the same temperature, humidity, machine, operator, the same amount of glue at the same temperature and compare those results after the same drying time. 

Fiber Tear Testing

A paper straw fiber tear test verifies that the amount of adhesive will enable production of a strong straw. The paper manufacturer can conduct this test themselves or work with H.B. Fuller to do so as part of their quality control process. Assessing the fiber tear performance at the end of the line is the first test. Achieving fiber tear at the end of the line verifies that the machine is operating as expected and that the amount of adhesive used will form a strong bond. A strong bond is essential to water resistance. 

Liquid-Resistance Testing

This test evaluates how long it takes for flagging, or unraveling, to occur when the straws are submerged in liquid. This is the most important quality control test. It is conducted a minimum of 24 hours after the adhesive is applied. To correctly assess paper straw liquid resistance, the straw must be placed in a certain direction in the liquid. It is advised that you test the straw in the liquid on the weak end, which is where the outer layer is uncovered, versus the strong end of the straw. Once the straw is in the water, it can be stirred occasionally and assessed for how long it takes for the straw to demonstrate signs of flagging. 

H.B. Fuller Swift®tak Paper Straw Adhesives

H.B. Fuller’s Swift®tak water-based adhesives produce three hours of liquid resistance. These products run fast and create a durable straw. H.B. Fuller conducts robust product testing in our laboratories and have validated that the average straw using Swift®tak adhesives lasts two to three hours in water and more than five hours in carbonated soft drinks before the straw starts to unravel or become excessively soggy. Although liquid resistance performance is paper- and liquid-dependent, on average Swift®tak adhesives perform better than the paper straw industry’s requirements for two to three hours of liquid resistance. 

Paper Straw Liquid Resistance Testing

At H.B. Fuller, our team of experts are ready to provide the adhesive solutions the paper straw industry needs to continue to grow in popularity and usage. Connect with us today to learn more about manufacturing paper straws and our Swift®tak products.

 

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