How to test the sizing degree of pulp or cardboard?
施胶就是对纸浆或纸板进行处理，使其获得抵抗液体（如水、油、水蒸气等）渗透、扩散的性能，进而保证内装物不致受到水或潮气的侵蚀。施胶度的测试方法主要有墨水划线法、表面吸收重量法、吸水高度法、浸水后增重法、电导法、卷曲法、接触角法等。目前常用的测试方法是墨水划线法和表面吸收重量法。
(1)墨水划线法
墨水划线法适用于测定纸与纸板的施胶度，以用标准墨水划线时不扩散也不渗透的线条的最大宽度表示，单位是毫米。线条愈宽，表明施胶度愈高。按照国家标准GB460“纸与纸板施胶度测定法（墨水划线法)”进行试验。具体测试步骤包括以下几点。
①试样采集与处理。按GB450取样，切取150mm×150mm试样，正、反面各不少于3片,并按GB 10739的要求对试样进行温湿度预处理。
②划线前，According to试样产品的标准要求，调节划线器的划线宽度、墨水最大含量。若利用鸭嘴笔划线，鸭嘴笔上墨水高度应控制在45°角时的最大含量。
③将试样平铺在玻璃板上，利用墨水达到最大含量的划线器（或鸭嘴笔)，以100mm/s的速度沿与试样纵向成45°角的方向排划出长约l00mm 的线条。线条宽度由0.25mm开始，以0.25mm递增至2.0mm。划线时，鸭嘴笔应在线条的开始和末端各停留约1s。如果直接用鸭嘴笔对试样划线，鸭嘴笔应与玻璃板保持45°角，并对试样保持轻微的压力。
④待线条在标准温湿度下风干后，即按“纸张对墨水渗透和扩散比较板”测量出试样对墨水不渗透、不扩散时的最大线条宽度，也就是试样的施胶度。
(2)表面吸收重量法
①测试原理
表面吸收重量法以纸或纸板的一面与水接触，经一定的时间，表面吸收水分所能增加的重量表示，单位是g/m2。
②测试方法
按照国家标准GB 1540“纸与纸板施胶度的测定法（表面吸收重量法)”进行试验。测试仪器是表面吸收重量测定器，如图2所示，圆筐架内径是( 112.8±0.1)mm。
图2 表面吸收重量测定器
具体测试步骤如下。
a. Sample collection and processing. Sampling according to GB 450, cut at least 6 pieces of samples with a diameter of 125mm, weigh them with a balance with a sensitivity of 0.001g, and perform temperature and humidity pretreatment on the samples according to the requirements of GB10739.
b. Fill the round basket of the instrument with 100mL of pure water at (20±2)°C, the liquid level is flush with the mark on the needle tip in the center of the round basket, and then place the weighed sample on the mouth of the round basket , put the cover down, and fix the cover with the screws on the cover.
c. Turn over the round basket frame and start the stopwatch for timing. According to the time specified by the sample product, turn the round basket frame to the right 10-15s in advance, take out the sample horizontally, and sandwich it in two layers of 200g/m2 industrial filter paper, put it on the cover and press it back and forth with a rubber roller, and absorb the sample. Excess moisture on the surface of the sample to dull, take out the sample and weigh it quickly, accurate to 0.001g. The test is carried out on the front and back sides of the sample respectively, and only one side of each sample is measured.
d. Calculate the surface absorbed weight.
The test results are expressed as the arithmetic mean of all measured values, and the maximum and minimum values are reported, accurate to 0.1g/m2.
